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John  S^vett 


RIE8. 

lasses, 


.  BeilsTein.  Translated  by  William  Ramsay,  D.Na.Sc 


Exlra  Volumes,  J2mo,  clolh. 

7d  APPLIED  MECHANICS     Bv  Heniiv  Evep.s,  LL  D 
15b  general  biology.    By  T.C.  MacGinley. 


IN    COURSE    OF    PUBLICATION. 


ADVANCED     SCIENCE     SERIES. 

Adapted  to  the  requirements  of  Students  hi  Science  and  Art  Classes 
and  Higher  and  Middle  Class  Schools. 

Printed  uniformly  in  Umo,  averaglna  350  pp..  fully  Illustrated,  cloth 

t.^lra,  Price  $1.50  each  vol. 

1.  PRACTICAL  PLANE  AND  SOLID  GEOMETPvY.  ByProfcscor 

F.  A.  Bradley,  London, 

2.  MACHINE    CONSTRUCTION    AND    DRAWING.       By   E. 

ToMKiNs,  Liverpool. 

3.  BUILDING  CONSTRUCTION.    By  R.  S.  Burn,  C.E. 

4.  NAVAL  architecture-Laying  Off  and  Shipbuilding. 

By  S.  J.  P.  Thearle,  F. R.S.N. A.,  London. 

5.  PURE  MATHEMATICS.     By  E.  Atkins,  Leicester.     2  vols. 

6.  THEORETICAL  MECHANICS.  By.  P.  Guthrie  Tait,  Professor 

of  Natural  Philosophy,  Edinburgh. 

7.  APPLIED  MECHANICS.      By  Professor  0.  Reynolds. 

8.  ACOUSTICS,  LIGHT,  AND  HEAT.    By  W.  S.  Davis,  LL.D. 

9.  MAGNETISM  AND  ELECTRICITY.     By  F.  Guthrie,  B.A., 

Ph.D.,  Royal  School  of  Mines,  London. 

10.  INORGANIC  CHEMISTRY.  By  T.E.  Thorpe,  Ph.D.,  F.R.S.E., 

Professor  of  Chemistry,  Glasgow.     2  vols. 

11.  ORGANIC  CHEMISTRY.    By  James  Dewar,  F.R.S.E.,  F.C.S., 

Lecturer  on  Chemistry,  Edinburgh. 

12.  GEOLOGY.  By  John  Young,  M.D.,  Professor  of  Natural  History, 

Glasgow  University. 

13.  MINERALOGY.     By  J.  H.  Collins,  F.G.S.,  Falmouth. 

14.  ANIMAL   PHYSIOLOGY.       By   J.    Cleland,    :M.D.,  F.R.S., 

Professor  of  Anatomy  and  Physiology,  Galway. 

15.  ZOOLOGY.    By  E.  Ray  Lankester,  M.A.  (Oxon.),  London. 

16  VEGETABLE   ANATOMY   AND   PHYSIOLOGY.      By  J.  H. 
Balfour,  M.D.,  Edinburgh  University. 

17.  SYSTEMATIC  AND  ECONOMIC  BOTANY.  By  J.H.  Balfour, 
M.D.,  Edinburgh  University. 

19.  METALLURGY.  By  W.  H.  Greenwood,  A.R.S.M.    2  vols. 

20.  NAVIGATION.     By  Henry  Evers,  LL.D.,  Plymouth. 

21.  NAUTICAL  ASTRONOMY.    By  Henry  Evers,  LL.D. 

22.  STEAM  AND  THE  STEAM  ENGINE— Land,  Marine,  A27D 

Locomotive.     By  H.  Evers,  LL.D.,  Plymouth. 

23.  PHYSICAL  GEOGRAPHY.     By  John  Young,  M.D.,  Professor 

of  Natural  History,  Glasgow  University. 


«Mav 


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PHYSICAL    GEOGRAPHY. 


v^M/C 


.         ,        it*        ' 


'        t         t  "  C     C    t  f   ,     ,     •    c     '  c  ' 


ATLASES  OF  PHYSICAL  GEOGRAPHY. 


In  Demy  8vo,  Stiff  Cover,  Is., 

THE  PFJMARY  ATLAS  OP  PHYSICAL  GEOGRAPHY, 

16  Maps,  9  by  11  inches. 


In  Demy  Svo,  Cloth  Limp,  2s., 

THE  POCKET   ATLAS   OP   PHYSICAL   GEOGRAPHY. 
16  Mcaps,  mounted  on  Guards. 


In  Imp.  Svo,  Cloth  Lettered,  Ss.  6d., 

THE  PORTABLE   ATLAS   OP   PHYSICAL   GEOGRAPHY. 
20  Maps,  11  by  13  inches,  mounted  on  Guards. 


In  Imp.  Svo,  Cloth  Lettered,  53., 

THE  STUDENT'S  ATLAS  OF  PHYSICAL  GEOGRAPHY. 

Twenty  Maps,  mounted  on  Guards. 

With  Letterpress  Description  and  Wood  Engravings. 

By  James  Bryce,  LL.D.,  F.G.S. 


IPutnam's  0mxmhx^  Btuixu  S'txm. 


PHYSICAL    GEOGRAPHY. 


FOR   USE   IN 


SCIENCE  CLASSES  AND  HIGHER  AND  MIDDLE 

CLASS  SCHOOLS. 


BY 


JOHN    MACTURK,    F.R.G.a 


'   / 


^ 


NEW    YORK: 
GEORGE  P.  PUTNAM'S  SONS, 

182  FIFTH  AVENUE. 


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K"o  effort  has  been  spared  to  render  the  present  work 
%yortliy  of  its  place  in  a  Series  of  Science  Text-Books, 
tliat  shall  be  at  once  popular,  accm-ate,  and  scientific.  It 
has  been  thoroughly  adapted  to  the  requirements  of  the 
Syllabus  for  Elementary  Physical  Geogi^aphy  of  the 
Science  and  Art  Department;  and  every  statement  has 
been  carefully  revised  in  the  light  of  the  most  recent  and 
reliable  information.  By  means  of  Maps,  Woodcuts, 
Diagi'ams,  and  descriptive  details — so  far  as  was  consistent 
with  the  linnts  of  the  work — it  has  been  attempted  to 
impart  pei'spicuity  and  interest  to  the  subject.  For  further 
information  on  several  points,  the  student  is  referred  to 
the  Atlases  constructed  by  Mr.  E.  Weller,  and  issued 
by  the  Publishers  of  this  work. 

In  order  to  render  the  study  as  practical  as  possil>Ir>, 
exercises  have  been  freely  introduced;  but  they  are  by 
no  means  intended  to  supei*sede  careful  and  minute 
questioning  by  the  teacher.  They  are  for  the  most  part 
of  a  suggestive  character,  fonning  in  fiict  an  expansion 
of  the  text;  from  which,  tlierefore,  they  are  not  in  every 
case  capable  of  bein^  answcttid  ^Ui-ectlv.     They  may  j'H. 


6  PREFACE. 

liowcver,  be  mastered  without  dilHculty  by  tbe  intelligent 
student,  with  the  aid  of  a  little  reflection,  Avhich  they  are 
intended  to  promote. 

For  the  sake  of  easy  reference,  a  carefully  prepared 

Index  has  been  added.     To  familiarise  the  student  with 

the  style  of  examination   to  which  he  may  be  subjected, 

recent  examination  papers  of  the  department  have  been 

appended. 

J.  M. 

TiLLicouLiTwY,  January,  1S73, 


CONTENTS. 


t\rr. 

lymoDUCTioy,  •  •  -  -  •  •      *J 

CHAPTER  I. 
DisirviEUTioN  OF  Land  aisd  Water,  -  -  -    10 

CHAPTER  II. 
Vertical  Configuration  of  the  Land,     •  •  -    23 

CHAPTER  IIL 
The  Waters  of  the  Oce.^,  -  -  -  '    ^^ 

CHAPTER  IV. 
The  Waters  of  the  Land,  -  -  •  •  -    C7 

CHAPTER  V. 
The  Atjiospheri:,       -  -  :  •  •  •    Gl 

CHAPTER  VL 
Structure  of  tiie  Earth,    -  -  -  •  -  112 

CHAPTER  VII. 
Distribution  of  Plants,       -  -  -  •  -131 

CHAPTER  VIIL 
Distribution  of  xIndials,    -  -  -  •  -133 

CHAPTER  IX. 

M.\NKIND,  -  .--•••   1-13 

Specimen  Examination  Papers,       .  -  .  .  149 

Index,-  ».•••••  152 


CONTENTS. 


MAPS. 


PACE 


TIjg  Ilemisplieres,  with  Heights  of  Mountains  and  Lengths  of 

llivers,       ..-----9 
Ocean  Currents  and  Pdver  Basins,       -  -  -  -    61 

Winds  and  Plains,         -  •  •  -  •  -    87 

Volcanoes  and  Earthquakes,    -  -  •  ■  -  ]19 

Distribution  of  Plants,  -  .  -  •  -  133 


"WOODCUTS. 

Tklathematical  Divisions  of  the  Earth,             -            •  -    11 

Land  and  Water  Hemispheres,             -             -            •  •     17 

Vertical  Sections  of  the  Continents,  -              -            -  -     24 

Section  of  the  Plateau  of  Mexico,       -            •            •  -     37 

Section  of  the  Plateau  of  Bolivia,        -             •            -  -     38 

Vertical  Section  of  the  Atlantic  Ocean,           -             -  -     55 

The  Sun  and  Moon  in  Conjunction  causing  Spring  Tides,  -     59 

The  Sun  and  Moon  in  Opposition  causing  Neap  Tides,  -     59 

Transtratic  Spring,       -             -             -             -             -  -     68 

Falls  of  Niagara,           -             -             •             -             -  -73 

Delta  of  the  Nile,         -            -            -            -            -  -    74 

The  Simoom,     -            -            -            -            -            -  -    91 

Cirrus  or  Curl  Cloud, 100 

Cumulus  or  Summer  Cloud,     -             -             -            -  -  100 

Stratus  or  Fall  Cloud,  -             -             -            •             -  -  101 
Snow  Crystals,               ...--.  107 
Glacier  of  the  Alps,      ------  108 

Section  of  the  Earth's  Crust,  -             -             -             -  -  114 

Crater  of  Vesuvius  during  an  Eruption,          -            -  -  120 

Vesuvius  not  in  a  State  of  Eruption,  -             -            -  -  121 

Earthquake  Fissiu-es  in  Calabria,         -            -            -  -  127 

Lagoon  Island  or  Atoll  and  Volcanic  Island,  -            -  -  129 

Vertical  Distribution  of  Plants,           -             -             -  -  134 

Bread  Fruit,      -             -             -             -             -            -  -  135 

The  Apteryx,    -             -             -             -            -            -  -   141 

Chief  Varieties  of  Manivind,    -----  145 


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PHYSICAL    GEOGRAPHY. 


IXTrvODUCTION. 

Physical  Geography  is  tliat  department  of  Geogi-apLy 
^vhich  relates  to  tlie  great  natural  features  and  arrange- 
ments of  the  globe.     It  treats  of  : 

(1)  The  Land,  as  to  its  extent,  distribution,  configura- 
tion, and  structure ; 

(2)  The  Waters,  as  to  tlieir  extent,  distribution,  con- 
figuration, composition,  and  movements ; 

(3)  The  Atmosphere,  as  to  its  composition,  currents, 
vapours,  and  temperature,  and  therefore  climate  ;  and. 

(4)  The  Distribution  of  Animal  and  Vegetable  Life. 

FORM,  SIZE,  A^'D  ^lOTIOXS  OF  THE  EAFvTH. 

Form  of  the  Earth. — The  form  of  the  Earth  is  nearly 
that  of  a  globe  or  sphere — not  being  perfectly  round,  but 
compressed  or  flattened  on  two  opposite  sides,  somewhat 
like  an  orange. 

Such  a  figure  is  termed  an  ohiate  spheroid. 

The  iiiliabitants  of  tlie  globe,  on  the  opposite  side  from  ns, 
have  their  feet  turned  towards  ours,  and  are  therefore  termed 
Antipodes. 

Proofs  of  the  Earth's  Rotundity.  —  (1)  Our  circle  of  vision 
becomes  wider  the  greater  the  elevation  of  our  position  on  the 
earth's  surface. 

(2)  The  tops  of  masts,  towers,  and  mountains  are,  on  approach- 
ing them,  first  observed,  and  afterwards  the  lower  portions. 

(.3)  In  travelling  a  great  distance  north  or  south,  new  stars 
aj^ear  La  view  in  advance,  while  others  disappear  behind  us. 


10  riiYSiCAt  -^eoghapiiy. 

(i)  In  circumnavigating  tlic  globe,  navigators  sailing  due  west 
or  east,  arrive  at  their  point  of  departure. 

(5)  The  shadow  of  the  earth  uijon  the  moon  during  an  eclipse 
is  always  round. 

((3)  In  making  a  canal,  allowance  must  be  made  for  a  dip  of 
eight  inches  in  each  mile  to  keep  the  water  at  a  uniform  dejjth. 

Size  of  the  Earth. — Tho  mean  diameter  of  the  Earth 
is  7912  miles  (or  nearly  8000  miles) — the  Equatorial,  or 
larger  diameter,  being  7925  miles,  and  the  Polar,  7899. 

If  the  Equatorial  diameter  were  divided  into  300  equal  parts, 
tlie  Polar  diameter  would  measure  299  of  them;  that  is,  it  is 
73^75-  shorter.  In  an  artificial  globe  of  18  inches  diameter,  this 
deviation  from  the  s^jherical  form  v/ould  amount  to  about  xV  P^^^ 
of  an  inch. 

The  Circumference  of  the  Earth  is  24,856  miles  (or 
nearly  25,000  miles);  the  Area,  or  superficial  content, 
197,000,000  square  miles;  the  Volume,  or  solid  con- 
tent, 200,000,000,000  cubic  mHes;  and  the  Weig'ht, 
5,425,092,500,000,000,000,000  tons. 

Motions  of  the  Earth. — The  Earth  has  three  motions  :— 

(1)  The  motion  through  space  along  with  the  rest  of 
the  Solar  System. 

(2)  Its  annual  motion,  or  revolution  round  the  Sun 
in  about  365|-  days. 

(3)  Its  diurnal  motion,  or  rotation  ou  its  o^vn  axis, 
in  about  24  hours. 

The  Earth's  motion  round  the  Sun  causes  the  changes  of  the 
seasons  and  the  difference  in  the  length  of  day  and  night:  its 
motion  on  its  o^vn  axis  causes  the  apparent  rising  and  setting  of 
the  Sun,  or  the  alternation  of  day  and  night. 

The  Earth's  Orhit,  or  path  round  the  Sun,  is  about  184,000,000 
miles  in  mean  diameter,  and  565,000,000  in  circumference.  Its 
form  is  not  a  circle,  but  rather  an  ellipse,  so  that  the  earth  is  not 
equally  distant  from  the  sun  at  all  pei'iods  of  the  year ;  its  peri- 
helion, or  nearest  point,  being  at  the  beginning  of  the  year,  or 
northern  winter,  and  its  aphelion,  or  farthest  point,  about  the 
middle  of  the  year,  or  northern  summer.  As  the  differ<ince  is 
only  about  3,000,000  miles,  it  has  no  perceptible  influence  on  the 
degree  of  solar  heat,  which  is  greatest  in  summer,  when  the  sv;n 
is  most  nearly  vertical,  and  least  in  winter,  when  his  rays  fall 
more  slantingly  on  the  earth. 


iiatiie:iatical  divisions  of  the  earth. 


11 


DEFIXITI0X3. 

!.L\THEMATICAL  DIVISIONS  OF  THE  EAniH. 

The  Axis  of  the  earth  is  an  imao^nary  line  which  pas-iC3 
throucfh  its  centre,  and  round  which  it  rotates  daily. 

The  North  and  South  Poles  are  the  extreme  points  of 
the  Axis. 

The  Equator  is  a  great  circle  passing  round  the  middle 
of  the  earth,  at  an  equal  distance  from  the  Poles. 

A  Hemisphere  is  one-half  of  the  earth  considered  as  a 
globe  or  sphere. 


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lIATnEMATICAL  DIVISIOXS  OF  THE  EARTH. 

The  Meridians  are  gi'eat  circles  passing  round  the 
earth  at  right  angles  to  the  Equator,  and  cutting  euch 
other  at  the  Poles. 


12  PHYSICAL   GEOGRAPHY.  * 

A  Semi-Meridian  is  that  half  of  a  Meridian  wliich  ter- 
minates in  the  Poles. 

The  Northern  and  Southern  Hemispheres  are  formed  by  the 
Equator ;  the  Eastern  and  Western  Hemispheres  by  Meridians. 

Latitude  is  the  distance  of  a  place  north  or  south  of 
the  Equator. 

Longitude  is  the  distance  of  a  place  east  or  west  of 
any  given  semi-meridian. 

Longitude  is  reckoned  by  the  British  from  the  semi-meridian  ©f 
Greenwich,  which  is,  on  that  account,  called  the  First  Meridian. 

Parallels  of  Latitude  are  lines  drawn  parallel  to  the 
Equator,  and  are  used  to  indicate  latitude. 

The  Tropics  are  two  remarkable  Parallels  of  Latitude, 
viz. : 

The  Tropic  of  Cancer,  nearly  23^°  north  of  the  Equator  ; 

The  Tropic  of  Capricorn,  nearly  23^°  south  of  the  Equator. 

The  Polar  Circles  a.re  two  remarkable  Parallels  of  Lati- 
tude, viz.  : 

The  Arctic  Circle,  nearly  23^°  from  the  North  Pole ; 
The  Antarctic  Circle,  nearly  2Z}/  from  the  South  Pole. 

The  Ecliptic  is  a  great  circle,  cutting  the  Equator  at 
two  opposite  points  at  an  angle  of  nearly  23J°,  and  reach- 
ing the  Tropics  as  its  extreme  limits  north  and  south. 
It  represents  the  sun's  apparent  path  through  the  heavens 
in  the  course  of  a  year;  but  in  reality  the  path  of  the 
earth  round  the  sun. 

The  Equator,  Ecliptic,  Keridians,  and  Parallels,  are  not  real, 
but  imaginary,  lines  on  the  earth's  surface,  and  are  drawn  on 
maps  and  artificial  globes  for  convenience  in  determining  the 
position  of  places. 

The  Zones  are  Five  Great  Belts  into  which  the  earth  is 
divided  by  the  Tropics  and  the  Polar  Circles,  viz  : 

The  Torrid  Zone,  between  the  Tropics  ; 

Two  Temperate  Zones,  between  the  Tropics  and  the 
Polar  Circles ; 

Two  Frigid  Zones,  between  the  Polar  Cii'cles  and  the 
Poles. 

Characteristics  of  the  Zones. — The  Zones  are  chiefly  distin- 
guished by  their  climatic  differences : — 


NATURAL   DIVISIONS    OF   THE   EARTH'S   SURFACE.       13 

Tlie  Torrid  Zone,  so  called  from  it3  scorcJiing  heat,  has  the  sun 
vertical  twice  in  the  year,  the  days  and  niglits  dilTer  little  iu 
length  throughout  the  year,  and  vegetation  is  most  luxuriant. 

The  Temperate  Zones  have  a  milder  or  temperate  climate,  the 
sun  never  being  vertical,  the  days  and  nights  are  more  unequal, 
the  four  seasons  are  more  distinct,  and  the  productions  of  tho 
earth  less  rich  and  eruberant  than  in  the  Torrid  Zone. 

The  Frigid  Zones,  so  called  from  their  extieme  cold,  have  one 
long  intensely  cold  winter,  when  for  several  weeks  the  sun 
never  rises,  and  one  short  hot  summer,  when  for  several  Aveeks 
the  sun  never  sets  (the  period  being  longer  or  shorter  at  different 
places  according  to  the  latitude).  Vegetation  is  scanty  and 
stunted. 

Comparative  Areas  of  the  Zones. — Suppose  the  entire  surface 
of  the  earth  divided  into  100  equal  parts  : 

The  Torrid  Zone  would  be  =  40  parts. 

Two  Temperate  Zones,  each  26,  =  52    ,, 
Two  Frigid  Zones,  each  4,  =     8    ,, 

100 


KATUPvAL  DIVISIONS  OF  THE  EARTH'S  SURFACR 

Land. 

A  Continent  is  a  large  continuous  extent  of  land  com- 
prising several  countries. 

An  Island  is  a  smaller  portion  of  land  than  a  conti- 
nent, and  is  wholly  surrounded  by  water. 

An  Archipelag'O  consists  of  several  groups  or  clusters 
of  islands. 

"The  Archipelago"  is  the  name  applied  to  the  iS'ffa  between 
Greece  and  Asia  Minor,  and  not  to  the  islands  contained  in  it. 

A  Peninsula  is  land  almost  wholly  sun-ounded  by  water. 

An  Isthmus  is  a  narrow  neck  of  land  joining  two 
larger  portions  of  land  together. 

A  Cape  is  a  point  of  land  stretching  out  into  the 
water. 

A  Cape  is  also  called  a  Promontory,  Point,  Head,  Headland, 
Mull,  Naze,  or  Xess. 

A  Coast  or  Shore  is  the  margin  of  land  washed  by  tlio 
sea. 


li  PHYSICAL   GEOGRArnT. 

The  Sea-Board  is  the  strip  of  country  bordering  on  the 
sea. 

A  Mountain  is  a  mass  of  hind  raised  considerably 
above  the  surrounding  surface. 

A  Hill  is  a  lower  elevation  than  a  Mountain. 

A  Moimtain  Cliain,  or  Range,  is  a  continuous  line  of  ]\Iountain 
heights. 

A  Group  of  Mountains  consists  of  a  number  of  heights  or 
ranges,  more  or  less  connected. 

A  Mountain  System  consists  of  a  scries  of  Mountain  Chains  or 
Groups. 

A  Volcano  is  a  Mountain  which  casts  forth  smoke,  flames, 
ashes,  lava,  etc. 

A  Valley  is  a  hollow  or  low  land  lying  between  Mountains  or 
Hills. 

A  Plain  is  a  flat  extent  of  land  not  much  raised  above 
the  level  of  the  ocean. 

A  Plateau  or  Table-Land  is  a  plain  considerably  ele- 
vated above  the  level  of  the  ocean. 

A  scries  of  Plains  at  different  levels  are  named  Terraces. 

Plains  have  received  specific  names  in  dififerent  parts  of  the 
world ;  as.  Prairies  and  Savannas,  in  North  America  ;  Pampas, 
Llanos,  and  Selvas,  in  South  America  ;  Steppes,  in  the  south-east 
of  Europe  and  the  north-west  of  Asia. 

Water. 

The  Ocean  or  the  Sea  is  the  general  name  applied  to 
the  great  continuous  expanse  of  salt  water  which  surrounds 
the  globe. 

An  Ocean  is  one  of  the  five  large  divisions  of  the  waters 
of  the  globe. 

A  Sea  is  a  smaller  body  of  salt  water  than  an  ocean, 
and  more  or  less  detached  from  it. 

Inlet  is  the  general  name  for  all  openings  or  indenta- 
tions of  the  sea-coast. 

A  Gulf  is  a  portion  of  water  running  into  the  land, 
and  having  a  narrow  opening. 

A  Bay  is  a  portion  of  water  running  into  the  land,  but 
having  a  wider  opening  than  a  gulf. 

The  terms  Gulf  and  Bay  are  frecj^uently  misapplied— the  one 
being  used  for  the  other. 


NATURAL   DIVISIONS    OF   THE   EARTIl's   SURFACE.       15 

Eoads  or  Roadstead  is  a  place  where  ships  may  be  moored  at 
801J10  distance  from  the  land. 

A  Harbour  or  Haven  is  an  inlet  where  shfps  may  be  moored 
anil  obtain  shelter. 

A  Creek  is  a  small  inlet  on  a  low  coast.  In  Australia  and 
America  it  means  a  small  inland  river. 

A  Strait  or  Sound  is  a  narrow  passage  of  water  uniting 
two  larger  portions  of  ■water. 

A  Channel  is  a  wider  passage  than  a  Strait. 

A  Bank  is  elevated  ground  at  the  bottom  of  tlie  sea, 
and  rising  to  near  the  surface. 

Banks  are  also  termed  Flats,  Shoals,  Shelves,  or  Shallows;  if 
at  the  surface,  they  are  termed  Eecfs;  if  above  the  surface,  tlicy 
would  form  islands. 

A  Lake  is  a  body  of  water  surrounded  by  land. 

A  Lagoon  is  a  shallow  lake  formed  on  low  lauds  by  the  over- 
flow of  rivers  or  the  sea. 

A  River  is  a  considerable  stream  of  fresli  w^ater  run- 
ning through  the  land  into  the  sea,  a  lake,  or  another 
river. 

A  Rivulet  or  Brook  is  a  small  stream  of  water. 

A  Tributary  or  Affluent  is  a  river  that  falls  into  another  river. 

The  Confluence  is  the  point  w'hcre  two  rivers  meet. 

The  Source  of  a  river  is  the  place  where  it  rises. 

The  Mouth  of  a  river  is  the  place  where  it  empties  itself. 

An  Estuai-y  or  Firth  is  the  mouth  of  a  river  widening  into  an 
arm  of  the  sea. 

The  Banks  arc  the  portions  of  land  bordering  on  each  side  of  a 
river.  The  right  and  left  banks  are  those  to  the  right  and  left 
of  a  person  looking  do^vll  the  river. 

The  Bed  of  a  river  is  the  channel  which  contains  its  waters. 

The  Basin  of  a  river  is  that  portion  of  country  which 
is  drained  bv  tlie  river  and  all  its  tributaries. 

A  Watershed  is  the  ridge  or  elevated  land  which 
separates  one  river-basin  from  another. 

A  River-System  consists  of  all  the  river-baskis  inclined 
to  any  particular  sea  or  ocean. 

A  Delta  is  a  low  tract  of  alluvial  land  deposited  at 
the  mouths  of  certain  rivers,  and  dividing  them  into  two 
or  more  streams;  so  called  from  its  resemblance  to  tho 
Greek  letter  a,  named  "  delta." 


16  PHYSICAL   GEOGRAPHY. 

CHAPTER  I. 
DISTRIBUTION  OF  LAND  AND  WATER. 

General  Aspect — Helative  Proportions — Configuration  of  tlio 
Land  (Horizontal) — Points  of  Kesemblance — Coast  Lines — 
The  Island  System. 

V  1.  General  Aspect. — On  glancing  at  the  map  of  tho 
world,  or  at  a  terrestrial  globe,  we  cannot  fail  to  observe 
the  very  unequal  extent  and  distribution  of  the  land  and 
sea  which  occupy  its  surface.  Surrounding  the  globe  on 
all  sides,  we  find  one  vast  continuous  expanse  of  water, 
with  two  large  continental  masses  of  land  emerging  from 
its  bosom,  and  a  great  many  smaller  ones  scattered  over 
it,  either  isolated  or  grouped  into  archipelagoes.  These 
two  great  continents  at  the  Arctic  Circle  approach  to 
within  36  miles  of  each  other,  and  then  recede  respec- 
tively in  a  south-easterly  and  south-westerly  direction, 
till  they  reach  points  far  into  the  southern  hemisjohere, 
with  three-fourths  of  the  earth's  circuit  between  them. 
The  latter  of  these,  called  the  Eastern  Continent, 
from  being  commonly  projected  upon  the  Eastern  Hemi- 
sphere, or  the  Old  World,  as  being  the  only  one  known 
to  the  ancients,  extends  in  a  direct  line  between  these 
two  extreme  points,  a  distance  of  11,000  miles;  whilst 
the  former,  styled  the  Western  Continent,  or  New  World, 
stretches  upwards  of  9,000  miles,  or  more  than  one-third  of 
the  circumference  of  the  globe.  To  the  south-east  of  Asia 
appears  the  vast  island  or  continent  of  Australia,  forming 
the  nucleus  of  that  great  island-system  of  the  southern 
seas  which  has  been  termed  Australasia ;  but  the  whole 
island- world  lying  east  of  the  Old  World,  and  west  of  the 
New,  is  known  by  the  name  of  Oceania. 

2.  Relative  Proportions. — The  entii-e  area  of  the  globe 
is  nearly  197  millions  of  square  miles.  Of  this  about  145 
millions  are  water,  and  52  millions  land ;  or  about  ^J^ 
water,  and  ^/i  land.    Considered  in  hemispheres,  the  land 


BELATIVE    PKOPORTIONS, 


17 


of  the  Eastern  is  about  2  ^/2  times  that  of  the  Western ; 
while  the  land  of  the  Northern  Hemisphere  is  about 
3  times  that  of  the  Southern.  If  we  compare  the 
different  zones,  we  lind  the  land  most  largely  developed 
in  the  North  Temperate  Zone, — forming  more  than  ^/2  of 
the  whole  area ;  while  that  of  the  Torrid  Zone  forms  no 
more  than  ^3.  The  great  belt  of  the  North  Temperate 
Zone,  embracing  the  better  portions  of  Asia,  Europe,  and 
North  America,  has  proved  the  most  favourable  to  the 
development  and  progress  of  the  human  race,  and  is  the 
great  track  along  which  civilization  has  hitherto  advanced. 


LAND   A^•D   WATER   HEMISPHERES. 


But  SO  unequally  distributed  are  the  land  and  water,  that 
not  more  than  ^27  of  ^-he  whole  land  surface  of  the  globe 
has  land  for  its  antipodes,  and  at  the  Equator  only  ^6  of 
the  whole  circumference  is  composed  of  land.  In  fact,  if 
we  divide  the  globe  into  two  hemispheres — the  one  hav- 
ing London  as  its  centre,*  and  the  other  Antipodes  Island, 

.*  London  is  not  the  exact  centre  of  the  Land  Hemisphere,  but 
a  spot  near  the  middle  of  St.  George's  Chaimel.  But  this  posi- 
tion of  London,  in  the  very  centre  of  the  nations  may  serve  not 
a  little  to  explain  its  greatness  and  commercial  prosperity,  and 
to  indicate  its  apparent  destiny  as  a  centre  of  influence  to  the 
world.  For  the  same  reason,  the  ports  of  the  adjoining  shores 
have  also  become  the  great  rendezvous  of  nations,  and  the  busy 
marts  of  commerce, 

23  B  B 


18 


PHYSICAL    GEOGRAPHY. 


near  New  Zealand — the  former  will  embrace   ^/lO  of  all 
the  land,  and  the  latter  will  bo  nearly  all  ocean. 

Size  of  the  Continents  (including  Islands.) 


EiiroDG 

Greatest 
Length. 

Greatest 
Breadth. 

Area  in  Sq. 
Miles.* 

Compara- 
tive size. 

3,400  M. 
6,700  „ 
5,000  „ 

5,600  „ 
4,500  „ 

io,oo6  „ 

2,450  M. 
5,400  „ 
4,G00  „ 

3,120  „ 
3,000  „ 

5,000  „ 

3,800,000 

17,000,000 

12,000,000 

(32,800,000) 

8,500,000 

7,000,000 
(15,500,000) 

4,500,000 

3,000,000 

It 
3^ 

O 

Asia, 

Africa, 

(Old  World), 

N.  America, 

S.  America, 

(New  World), 
Oceania, 

Australia, 

2,500  „ 

2,000  „ 

1 

Comparative  View  op  the  Areas  of  the  Continents, 
Heduced  to  Squares. 


>^ 


V. 


Miles. 
412^- 


SiG4 

291o 
204o 

1050. 
1732- 


Asia. 


Africa. 

North  America. 

South  America. 

Tfi 

Europe. 

1 

O 

g= 

■r-f- 

o 

*^ 

> 

P 

w 

■2 

0) 

c 

U 

l-« 

-I 

CD 

^» 

Australia. 

o 
►:3 

13, 

p 

o 

p 

h-" 

h-» 

tsS 

lO 

to 

*•  :r. 

-^ 

o 

O 

o 

(*- 

•—  CD 

to 

C-T 

t*» 

t-l 

o 

to  CO 

U« 

o 

w 

«x 

l{^ 

w- 

•  The  areas  are  given  in  round  numbers. 

t  Take  Europe  as  the  standard  of  comparison. 


CONFIGURATION    OF   THE   LAND.  19 


CONFIGUrcATIOX  OF  THE  LAND  (HORIZONTAL). 

3.  Points  of  Resemblance. — (1)  Whilst  the  mass  of 
the  land  in  the  Northern  Hemisj)here  lies,  for  the  most 
|xirt,  parallel  with  the  equator  and  along  the  great  zones, 
— its  greatest  extension  being  along  the  50tli  parallel, — • 
it  sends  forth  three  great  prolongations  to  the  south  : 
viz.,  South  America,  Africa,  and  Australasia — consider- 
ing the  last  as  a  continuation  of  Asia  partly  submarine. 

(2)  All  these  great  divisons  of  the  land  extend  in 
broad,  unbroken,  compact  masses  in  the  north,  but  taper 
gradually  to  the  south,  assuming  generally  a  triangular 
form.  The  northern  shores,  running  nearly  in  a  line 
along  the  70th  parallel,  and  almost  girdling  the  world, 
are  flat  and  low;  the  southern,  sundered  by  great  oceans, 
are  sharp  and  elevated. 

(3)  The  same  analogy  subsists  with  regard  to  the 
leading  peninsulas  of  the  world,  which  all  run  to  the 
south,  with  the  exception  of  Yucatan  in  Central  America, 
Jutland  in  Europe,  and  a  few  others.  The  latter  are 
low  and  sandy;  the  former  are  mostly  high  and  rocky. 

(4)  Most  of  the  peninsulas  have  an  island,  or  group  of 
islands,  near  theii-  extremities,  lying  frequently  to  the 
south-east.  Thus,  South  America  and  Africa  (which  are 
just  peninsulas  on  a  gigantic  scale)  have  respectively 
Tierra  del  Fuego  and  Madagascar ;  *  Florida  has  the 
"West  Indian  Archijielago,  and  Malacca  the  East  Indian ; 
Italy  has  Sicily;  India,  Ceylon ;  and  Australia,  Tas- 
mania. 

(5)  The  three  gi'eat  peninsulas  of  Europe  bear  a 
general  resemblance  to  those  of  Asia :  viz.,  the  Iberian 
peninsula  to  the  Arabian ;  Italy,  along  with  Sicily,  to 
India  with  Ceylon ;  and  Greece  ^\dth  its  archipelago,  to 
Malacca  with  the  East  Indian  Islands.  A  similar  analogy 

*  Immediately  to  the  south  of  the  Cape  of  Good  Hope  is 
L'Agulhas  Bank,  which  may  be  regarded  as  really  an  island,  bub 
not  appearing  above  the  water. 


20  PHYSICAL   GEOGRAPHY. 

may  be  traced  between  Mexico  and  India,  Florida  and 
Malacca,  the  "West  Indies  and  the  East  Indies. 

(6)  Nearly  the  same  meridians  cut  the  extreme  north 
and  the  extreme  south  points  of  the  great  continents  : 
with  this  view  compare  Cape  Horn  with  the  north-east 
end  of  Cockburn  Island,  Cape  of  Good  Hope  (as  well  as 
Cape  Matapan)  with  the  North  Cape,  Cape  Komania 
with  Cape  Severo. 

(7)  Africa  and  South  America  have  a  very  striking 
similarity  in  their  position  and  outline,  so  as  to  seem  the 
counterj^arts  of  each  other,  as  if  they  had  originally 
formed  one  mass  and  been  parted  by  some  great  agency. 
The  western  projection  in  the  north  of  Africa  would  fit 
into  the  great  aperture  on  the  opposite  shore  of  the 
Atlantic  formed  by  the  Caribbean  Sea,  while  the  project- 
ing part  of  South  America  would  fit  equally  well  into  the 
Gulf  of  Guinea. 

^''^  4.  Coast-Lines. — While  the  northern  continents  throw 
/out  numerous  arms  into  the  ocean,  and  are  in  return 
penetrated  by  numerous  gulfs,  bays,  and  inland  seas,  the 
southern  continents,  viz.,  South  America,  Africa,  and 
Australia,  present  each  a  solid  compact  mass, — their 
uniform  and  unbroken  coast-line  shutting  out  the  ad- 
vances of  the  ocean.  Asia  on  the  south  and  east  projects 
the  large  peninsulas  of  Arabia,  Hindostan,  Farther 
India,  the  Corea,  and  Kamtchatka,  with  China  and 
Manchooria,  which  together  form  Ys  of  its  whole  land- 
surface.  Europe,  whilst  itself  only  a  peninsula  of  Asia, 
is  subdivided  repeatedly  into  secondary  peninsulas,  so 
that  Y4  of  its  whole  mass  is  presented  under  that  form  ; 
while  land  and  sea  are  so  interlaced  that,  except  in  the 
east  of  Russia,  no  jAsice  is  more  than  500  miles  from  the 
coast.  It  is,  therefore,  of  all  the  continents,  the  most 
accessible,  and,  consequently,  the  most  favourably  situ- 
ated for  commerce  and  navigation,  and  the  development 
of  its  internal  resources.  North  America,  especially  on 
its  east  coast,  partakes  of  the  same  characteristic  featui'es, 
but  to  a  more  limited  extent. 


CONFIGURATION    OF    THE    LAND    (HORIZONTAL).  21 

The  possession  of  a  deeply-indented,  and  therefore  an 
extended,  coast-line,  has  a  most  important  bearing  upon 
the  climate,  and,  therefore,  upon  the  productions  of  a 
country,  as  well  as  the  health  and  character  of  the  in- 
habitants. To  the  facilities  it  has  afforded  to  the  enter- 
prise of  Europe  and  North  America,  which  excel  the  other 
continents  in  the  comparative  length  of  their  coast^line, 
may  be  ascribed  much  of  their  pre-eminent  wealth,  power, 
and  civilization. 


Table  of  Coast-Lines. 

Eurone 

Miles  of 
Cuast-Line. 

Sq.  !Miles  for 
1  Mile  of  Coast. 

Comparative 

Length  of 

Coast. 

17,000 
35,000 
16,000 
24,000 
13,600 
7,000 

225 
4S6 
750 
354 
515 
395 

1* 

h 

3 

Asia,  

Africa 

N.  America 

S.  America 

Australia 

5.  The  Island  System. — The  island  masses  differ  from 
the  continental  only  in  respect  to  size,  being,  in  fact,  for 
the  most  part,  continents  in  miniature.  They  are  por- 
tions of  the  same  solid  substance  of  the  globe,  rising  from 
the  floor  of  the  ocean,  but  their  inferior  elevation  permits 
only  a  smaller  surface  to  protmde.  Groups  and  chains 
of  islands  are  generally  the  crests  of  mountains  whose 
bases  are  at  the  bottom  of  the  ocean.  Austi-ulia  is  so 
large  as  to  be  frequently  called  a  continent — being  little 
inferior  to  Europe.  Some  are  so  small  as  to  be  only  a 
few  square  yards  in  extent,  uninhabited,  and  scantily 
clothed  with"^  soil  and  vegetation.  Others,  again,  are  so 
low  as  to  be  mere  sandbanks,  ledges  of  rock,  or  coral 
reefs.  The  larger  ones  are  nearly  all  contiguous  to  tho 
continents,  to  which,  in  their  geological  stmcture  and  tho 
direction  of  their  mountain  system,  they  bear  so  close  a 
relation.ship  as  to  be  considered  nearly  detached  portions 
*  Take  Europe  as  the  standard  of  comparison 


■  ^ 


22  rilYSlCAli   GEOGRAPHY. 

or  submarine  prolongations.  These  are  called  conti- 
nental islands.  The  smaller  ones,  either  solitary  or  in 
groups,  are  in  general  dispersed  over  the  oceans,  and  at 
great  distances  from  the  mainland.  These  are  the 
oceanic  islands,  and  are  either  of  volcanic  origin,  like  St. 
Helena  and  Ascension,  or  of  coralline  formation,  like  the 
thousands  of  islets  of  Polynesia.  The  most  important 
archijDelagoes  ov  island-groups  are  the  British,  Japanese, 
East  Indian,  West  Indian,  and  Grecian  ;  whilst  the  vast 
assemblage  of  island-forms  that  stud  the  wide  expanse  of 
the  Pacific,  has  nowhere  else  a  parallel.  The  largest  indi- 
vidual islands  (cot  including  Australia)  are  : — 

Greenland,      380,000  sq.  miles. 
Borneo,       .     280,000        ,, 
New  Guinea,  274,500 


Sumatra,   .     177,000  sq.  miles. 
Niphon,     .     100,000        „ 
Great  Britain,  85,828        „ 


Madagascar,    234,000 

But   taken   together,   the  whole  island-masses  form  no 
more  than  about  Y20  of  the  whole  land  area  of  the  globe. 


V 

EXERCISES. 

1.  Name  the  extreme  southern  points  of  the  great  continents 
and  Australasia.  How  far  are  they  from  the  Antarctic  Circle, 
and  from  each  other  ?  Give  the  direct  distances  (approximately) 
from  East  Cape  to  Cape  of  Good  Hope  and  to  Cape  Horn.  Given 
the  area  of  a  sphere  =  diameter ^  x  3 •1416,  and  the  mean  diameter 
of  the  globe  =  7912  miles;  supposing  the  earth  a  perfect  sphere, 
find  its  area.  Name  the  countries  or  islands  which  have  lands 
for  their  antipodes.  Point  out  iihe  meridians  of  most  land  and 
least  land.  Name  the  countries  not  included  in  the  land  hemi- 
sphere. Compare  the  area  of  each  of  the  Continents  with  that 
of  the  British  Islands,  (122,000  sq.  m.)       f- 

2.  Name  the  countries  along  the  50th  parallel.  What  islands 
most  nearly  connect  Australia  with  Asia  ?  Write  out  in  tabular 
form  the  leading  peninsulas  of  Europe,  Asia,  Africa,  North 
America,  and  South  America.  Name  a  peninsula  in  Europa 
running  west — one  in  Asia — one  in  America.  Give  other  ex- 
amples of  islands  situated  near  the  extremities  of  peninsulas. 
What  are  the  meridians  that  most  nearly  cut  the  extreme  north 
and  south  points  of  the  great  continents  ?    Write  out  in  your 


VERTICAL   CONFIGURATION   OF   THE    LAND.  23 

c-on  -words  the  leading  points  of  resemblance  in  the  outlines  of 

the  land.  *  a   • 

3.  Draw  t\\-o  lines  that  would  cut  off  all  the  peninsulas  of  Asia 
on  the  south  and  east.  Point  out  two  peninsulas  on  the  north 
of  Asia.  Name  those  peninsiilas  of  Europe  that  are  most  sub- 
di\nded.  Which  parts  of  North ^Vmerica  are  most  indented? 
Arrange  in  order  the  continents  according  to  extent  of  coast- 
line. Give  a  comparative  view  of  the  comparative  length  of 
coast -lines  by  means  of  a  scale,  or  other^vise.  What  two  islands 
in  the  Atlantic  are  most  distant  from  the  mainland  and  from 
others  ?  and  how  far  ?  Write  out  a  descriptive  account  of  tha 
Distribution  of  the  Land. 


CHAPTEr.  11. 

VERTICAL  CONFIGLTIATION  OF  THE  LAND. 

Forms  of  Vertical  Arrangement— Laws  of  Vertical  Arrangement 
— Configuration  of  Mountains — Mountain  Chains — Dimen- 
sions of  Principal  ^Mountain  Chains — Height  of  ^Mountains — 
Hills — Uses  of  ^Mountains — Principal  Mountains  of  the  Globe 
—Table-Lands  or  Plateaux— The  Sahara— Principal  Plateaux 
— Lowland  Plains — Steppes,  etc. — Prairies — Llanos — Pampas 
— Uses  of  Plains— Principal  Plains— Valleys— Mean  Eleva- 
tion of  the  Continents. 

6.  Forms  of  Vertical  Arrangement. — The  land-masses 
are  not  disposed  at  one  uniform  level,  but  assume  various 
forms  and  elevations.  There  are  the  low  flat  polders  of 
Holland  just  reclaimed  from  the  sea,  and  ^\^[tll  difficulty- 
retained  from  it;  river  deltas,  as  of  the  Nile  and  Ganges, 
where,  in  the  swimming  marsh,  the  contending  elements 
of  sea  and  dry  land  are  intermingled;  lowland  plains, 
flat  or  undulating,  and  but  little  raised  above  the  level 
of  the  sea;  elevated  plateaux  or  highland  plains;  and 
mountain  ranges,  with  their  cloud-capt  peaks  and  snow- 
clad  summits. 

Although,  to  the  casual  observer,  these  mountains  and 
valleys,  plains  and  plateaux,  may  appear  to  be  without 
order  or  regularity,  yet  a  more  careful  examination  will 


24 


PHYSICAL   GEOGRAPIir. 


VERTICAL    ARRANGEMENT    OF    THE    LAND.  25 

sliow  US  a  few  great  general  principles  presiding  over 
their  arrangement. 

7.  Laws  of  Vertical  Arrangement  of  the  Land.— 
(1)  The  continents  rise  graduall>/  from  the  shores- of  the 
ocean  into  the  interior  to  some  line  or  ridge  of  greatest 
elevation. 

These  slopes  may  be  easily  discovered  hy  casting  the 
eye  upon  the  map,  and  following  up  tlie  gi'eat  river- 
courses;  the  ridge  along  which  they  rise  is  the  line  of 
greatest  elevation.  To  'this  law  there  are  only  two  well- 
ascertained  exceptions,  and  they  are  remarkable.  The 
one  is  an  extensive  region  around  the  Caspian  Sea  and 
Lake  Aral,  with  an  area  of  102,000  square  miles  (five 
times  the  size  of  Ireland),  which  forms  so  great  a  depres- 
sion that  the  surface  of  the  Caspian,  which  is  its  lowest 
point,  is  83  feet  below  the  sea  level;  the  other  is  the 
basin  of  the  Dead  Sea,  the  surface  of  which  is  1312  feet 
below  the  Mediterranean. 

(2)  The  line  or  axis  of  greatest  elevation  is  placed ,  not  in 
the  centre,  but  nearer  to  one  side  of  the  continents. 

The  two  great  slopes  of  the  land  thus  formed  are,  in 
consequence,  of  unequal  length  and  inclination :  the  one 
long  and  gentle,  the  other  short  and  steep.  The  long 
slope  is,  on  an  average,  four  or  five  times  the  length  of 
the  other.  In  the  Old  \Yorld,  the  long  slope  is  to  the 
north ;  in  the  New  World,  to  the  east. 

Thus,  from  the  Himalayas,  the  highest  ridge  of  Asia,  to  the 
Frozen  Ocean,  at  the  mouth  of  the  Yenisei,  is  a  length  of  2G00 
miles,  but  south  to  the  Plains  of  Ilindostan  it  is  only  400 ;  from 
the  Alps  to  the  Baltic  is  450  miles,  but  south  to  the  Plain  of 
Northern  Italy  is  only  100;  from  the  Rocky  Mountains  to  the 
Atlantic  the  eastern  sloj^  is  IGOO  miles,  while  the  western  slope 
to  the  Pacific  is  800 ;  and  while  from  Chimborazo,  in  the  Antics 
of  South  America,  eastwards  to  the  mouth  of  tlK5  Amazon,  the  dis- 
tance is  1850  miles,  to  the  Pacific  westwards  it  is  less  than  100. 

If  we  consider  the  Northern  Ooean  as  an  extension  of 
the  Atlantic,  so  as  to  form  with  it  one  great  basin,  and 
ihe  Indian  Ocean  as  but  a  portion  of  the  basin  of  the 
Pacific,  the  long  slope  is  turned  towards  the  Atlantic 


^S  PitYSICAt   GEOGItAPHT. 

basin  and  tliG  sliort  slope  to  the  Pacific.  It  would  seem 
as  if  tlie  land-mass  bordering  on  tlie  latter  had  been  tilted 
lip,  so  as  to  throw  the  waters  off  chiefly  to  the  other  side. 
The  loftiest  mountains  in  the  world  surround  the  marofin 
of  this  mighty  basin  like  a  hem :  near  its  eastern  border 
a  great  chain  rises  abruptly  along  its  Avhole  extent  of 
9000  miles,  is  continued  through  the  Aleutian  Isles  into 
Central  and  Southern  Asia,  finds  its  way  by  the  highlands 
of  Arabia  into  Africa,  and  thence  southwards  alono:  the 
coast  to  the  Cape  of  Good  Hope.  An  immense  number 
of  active  volcanoes  blaze  around  this  extensive  margin, 
from  Tierra  del  Fuego  ("  Land  of  Fii^e")  to  Mount  Erebus 
in  South  Victoria  Land. 

(3)  The  grand  linear  elevations,  or  mountain  chains , 
extend  in  the  line  of  the  greatest  length  of  the  continents. 

In  other  words,  the  general  direction  of  the  mxountains 
determines  that  of  the  land;  for  mountains  are  the  skeleton 
of  the  lands,  and  determine  their  figure  and  outline  as 
truly  as  the  bones  do  those  of  an  animal.  The  great 
series  of  mountain  ranges  which  forms  the  line  of  greatest 
elevation,  is  the  backbone  of  the  continents.  Secondary 
ranges  of  inferior  elevation  branch  off  at  various  angles 
from  the  main  axis;  and  it  is  such  chains  that  are  chiefly 
concerned  in  the  formation  of  our  leadins:  islands  and 
joeninsulas.  They  are  the  ribs  and  limb-bones  in  the 
gTeat  framework  of  our  planet. 

In  the  Old  World,  whose  greatest  length  is  from  east  to  west,  or 
along  the  parallels,  an  almost  iinhroken  series  of  ridges  stretches 
in  the  same  general  direction  between  their  extreme  points. 
From  Cape  St.  Vincent  to  Behring's  Strait  (not  mentioning  infe- 
rior elevations)  the  connection  is  maintained  by  the  successive 
ranges  of  the  Sierra  ISIorena,  the  Pyrenees,  the  Alps,  the  Balkan, 
Taurus,  Elburz,  Hindoo  Koosh,  Bolor  Tagh,  the  Altai,  Yablonoi, 
Stanovoi,  and  Aldan  JSIountains.  In  the  New  World,  again, 
whose  greatest  length  is  from  north  to  south,  the  mountains  also 
follow  the  meridians — the  Rocky  Mountains  and  the  Andes  being 
the  chief  ranges  of  that  series  that  stretches  uninterruptedly  from 
Behring's  Strait  to  Cape  Horn.  The  Alleghanies  and  Cordilleras 
of  Brazil  preserve  the  same  general  direction.  The  mountains  of 
Africa,  so  far  as  certainly  luiown,  appear  to  follow  the  direction 


CONFIGURATION"   OF   MOUNTAINS.  2? 

of  the  coast-line ;  and  the  same  may  be  said  of  the  mountains  of 
Australia,  And  as  with  the  continents,  so  -svitli  the  chief  islands 
and  peninsulas :  Scandinavia  is  traversed  through  its  entire 
length  by  the  Scandinavian  Alps,  Italy  by  the  Apennines,  India 
by  the  Ghauts,  and  similarly  Madagascar,  Japan,  etc. 

(4)  The,  greatest  elevations  are  in  the  south  of  the  con- 
tinents, there  being  a  gradual  rise  from  the  Arctic  Circle, 
lehere  the  laiuls  are  lowest  and  flattest,  on  to  the  trojncal 
regions. 

The  culminating  point  of  the  Old  "World  (]\Iount  Everest) 
is  situated  near  tlio  Tropic  of  Cancer,  whilst  that  of  the 
New  World  (Aconcagua  in  Chili)  is  not  far  south  of  the 
Tropic  of  Capricorn.  As,  according  to  a  wcll-knoA\Ti  law, 
temperature  is  diminished  by  elevation,  the  lowness  of 
the  northern  sm-fiice  serves  to  mitigate  the  rigours  of  the 
Arctic  climate,  and  the  highlands  of  the  south  temper 
the  fierceness  of  the  tropical  heat.  "  If  this  order  were 
rev>3i'sed,  and  the  elevation  of  the  lands  went  on  increas- 
ing towards  the  Poles,  the  most  civilized  half  of  the 
globe  at  the  present  day  would  be  a  frozen  uninhabitable 
desert." 

MOUXTAIXS. 

8.  Configuration  of  Mountains. — Moimtains  are  the 
gi-andest  and  most  sublime  objects  on  the  surface  of  the 
globe.  They  present  every  variety  of  outline  and  appear- 
ance :  they  have  gently  sloping  declivities,  rounded  sum- 
mits, and  broad  massive  shoulders;  or  they  are  serrated 
Avith  splintered  peaks,  terraced  by  crags,  piled  up  like 
si^antic  battlements,  or  towering  into  cones,  domes,  and 
pyramids.  In  their  more  familiar  forms  they  may  be 
clothed  with  rich  green  pastures,  or  embrowned  with 
purple  lieaths;  but  their  grander  developments,  leaving 
the  realms  of  vegetation,  tower  high  into  the  desolation 
of  eternal  snows.  And  this  external  aspect  maintains  a 
close  correspondence  with  their  internal  structure.  The 
practised  eye  of  the  geologist  can  generally  determine 
from  their  outline  the  character  of  their  rocky  fonnationa 
— the  bald   and  massive  forms   of  gi-auite,  the   black, 


28  PHYSICAL   GEOGRAPHY. 

gloomy  walls  of  trap  and  basalt,  the  abrupt  splintered 
pinnacles  of  scliist  and  quartz,  the  round  undulations  of 
chalk,  and  the  isolated  cones  of  volcanoes. 

9.  Mountain  Chains. — It  is  rare  that  a  mountain  rises 
from  the  plain  in  complete  isolation  from  others;  and 
when  this  does  occur,  it  is  chiefly  in  the  case  of  heights 
of  volcanic  origin.  Among  the  more  remarkable  examples 
of  this  class  are  Mount  Egmont,  in  New  Zealand,  and 
the  Peak  of  Teneriffe  in  the  Canary  Islands.  The  most 
common  arrangement  is  that  of  chains,  frequently  con- 
sisting of  several  parallel  ridges,  the  centre  one  being 
the  highest.  These  chains  generally  reach  their  highest 
elevation  near  the  middle,  and  towards  their  extremities 
droop  gradually  down  into  the  plain.  The  lateral  ridges 
which  break  off  from  these  may  again,  in  their  turn,  send 
off  minor  ridges  or  spurs  in  numerous  ramifications. 

Mountain  chains  have,  in  general,  very  steep  declivi- 
ties on  one  side,  and  very  gradual  slopes  on  the  other ; 
the  latter  is  called  the  slope,  the  former  the  counter- 
slope.  The  Alps,  for  example,  descend  abruptly  towards 
Italy,  but  gently  toAvards  Switzerland  ;  and  the 
Pyrenees  are  steep  to  the  south,  but  sloping  towards  the 
north ;  while  the  Asturias  or  Oantabrian  Mountains  are 
the  reverse.  The  same  law  applies,  as  we  have  seen,  to 
the  land-masses  of  the  great  continents. 

These  chains  frequently  traverse  immense  regions,  form- 
ing the  barriers  of  great  nations  dwelling  around  their 
base.  The  Andes,  for  example,  continued  by  the  Mexican 
and  Rocky  Mountains,  extend  through  all  the  different 
zones  and  climates  of  the  world. 

10.  Height  of  Mountains. — To  the  eye  of  the  specta- 
tor, the  most  striking  feature  of  mountains  is  their 
height ;  and  it  might  be  readily  inferred  that  such  eleva- 
tions would  destroy  the  perfectly  spherical  form  of  the 
earth,  and  render  it  an  irregular  body.  But  although  the 
highest  mountain  of  the  globe  is  29,002  feet,  or  very 
nearly  5  J  miles  in  height,  it  is  only  Y1440  of  the  earth's 
diameter;  that  is  to  say,  it  would  be  correctly  represented 


niLLS. 


29 


by  a  gi'ain  of  sand,  Yso  of  an  incli  in  thickness,  laid  upon 
the  surface  of  an  artilicial  globe  18  inches  in  diameter. 
Yet  the  imagination  cannot  fail  to  be  impressed  with  the 
mass  and  majesty  of  Titanic  forms  rising  miles  into  the 
ail',  and  with  the  mysterious  solitudes  of  summits  unap- 
i^roachable  to  human  footsteps. 

The  Himalayas  exhibit  the  gi-eatest  elevations  as  well 
as  the  greatest  mass  of  any  mountain  system  of  the  globe; 
they  send  uj)  no  less  than  twenty-two  summits  above 
20,000  feet,  six  of  which  are  above  25,000.  Theii-  mean 
height,  according  to  Humboldt,  is  15,670  feet.  Whilst  the 
Andes  exceed  them  in  length,  they  are  of  inferior  eleva- 
tion, and  only  fourteen  summits  have  an  altitude  of  more 
than  20,000  feet.  Yet  the  mean  elevation  of  the  Andes 
is  11,830  feet,  and  their  bases  occupy  an  area  of  nearly 
one-sixth  part  of  the  continent  of  South  America. 

Dimensions  of  Principal  Mountain  Chains, 


CUAIN'. 


Lengtu. 


Alps, , 

Pyrenees, 

Apennines , 

Carpathians 

Balkan,  or  Hiemus, , 

Urals , 

Scanilina\1an  Mountains, 

Himalayas, 

Caucasus,  

Atlus, , 

Rocky  Mountains,*  

Appalachians,  or  Alle^jhanies,. 
Audes,  or  Cordilleras, 


600  Miles. 

300  „ 

800  ,, 

800  „ 

Ci)0  „ 

IGOO  „ 

lloO  „ 

1500  „ 

750  „ 

ICOO  „ 

5u00 

2000 

4ouO 


II 
I) 


Breadth. 


80  to 


200  M. 
00  „ 


1(3  to 

60  to 
100  to 

Oj  to 

50  to 
570  to  1040 
150  to    2o0 

40  to    400 


Co 

2o0 

100 

150 

90 


Mean- 
Height. 


7700  Feet. 
Suoo  „ 

4000   „ 

50U0 

40^0 

2000 

45u0 

15070 

85i'0 
7ooO 
5000 
i'.'.iiO 
IISJU 


11 
II 
II 


«i 
II 
II 


11.  Hills. — In  popular  language  the  term  hill  is  applied 
to  inferior  elevations,  and  mountains  to  higher  ones;  but 
there  is  a  ^\ider  distinction  between  them,  which  is 
geological  and  structural  rather  than  geographical  in 
character.      Mountains  consist  generally  of  oontinuoua 

*  Including  the  whole  Pacific  System;  Pocky  Mountains  pro- 
per, 3000  miles  long. 


30  PHYSICAL   GEOGRAPHY. 

groups  or  cliains,  while  hills  are  more  usually  isolated  or 
detached.  Mountains  are  fomied  of  the  older  and  harder 
rocks  which  have  been  upheaved  through  the  stratified 
and  softer  materials,  and  these  broken  and  soft  rocks 
have  been  worn  away,  at  least  in  great  part,  by  aqueous 
action.  Hills,  on  the  other  hand,  are  composed  more 
generally  of  the  soft  stratified  rocks  of  the  surroundmg 
country,  smoothed  and  rounded  by  the  action  of  the 
weather,  more  particularly  of  frost  and  rain.  The  former 
have  been  subject  to  aqueous  denudation,  the  latter  to 
aerial  denudation.  To  the  latter  process  are  due  tha 
irregularities  that  occur  in  the  surface  of  table-lands. 
Viewed  in  the  light  of  these  observations,  the  Malvern 
Hills  (1396  feet  high)  in  the  south-west  of  England,  are 
Ideally  mountains,  and  not  hills,  for  they  are  composed  of 
syenite. 

12.  Uses  of  Mountains. — Mountains  are  not  mere 
objects  of  interest  from  their  sublimity  or  beauty ;  they 
play  an  imjDortant  part  in  the  economy  of  nature.  Their 
summits  arrest  and  condense  the  moisture  of  the  atmos' 
phere  into  dews,  snows,  and  rains ;  and  from  bubbling 
spring  or  melting  glacier,  they  again  send  them  forth 
along  their  slopes  by  brooks  and  rivers,  to  refresh  and 
fertilize  the  plains  below.  "Whilst  in  all  countries  influ- 
entially  affecting  climate,  they  temper,  by  their  cooling 
breezes,  the  heat  of  Torrid  climes.  They  are  the  great 
treasuiies  of  our  mineral  wealth — even  the  golden  sands 
of  rivers  having  been  worn  and  washed  out  of  their  veins. 
They  increase  the  surface  of  the  earth ;  they  diversify  its 
productions;  and  they  give  richness  and  variety  to  the 
landscape.  While  their  snow-clad  summits  have  formed 
barriers,  even  more  impassable  than  the  ocean,  to  the  dis- 
persion of  plants  and  animals,  and  to  the  spread  of  the 
languages  and  races  of  mankind,  they  have  nursed 
Avithin  their  bosoms  generations  of  hardy  and  joatriotic 
men,  who  have  made  their  mountain-fastnesses  the  im- 
pregnable strongholds  of  freedom. 


FHYSICAL  GEOGRAniT. 


31 


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34  rilYSICAL   GEOGRAPHY 

TABLE-LANDS  OR  PLATEAUX. 

13.  The  greatest  mass  of  elevated  land  does  not  consist  of 
mountains,  but  is  spread  out  in  extensive  upland  plains, 
called  plateaux  or  table-lands.  These  plateaux  are  not 
necessarily  flat,  but  consist  of  considerable  areas  of  plain 
surface  high  above  sea-level,  and  may  be  varied  by  hill 
and  dale,  lake  and  river.  They  are  frequently  supported 
round  their  margins  by  mountain  ridges,  whose  abrupt 
descent  to  the  plains  below  imparts  that  table-like  form 
whence  they  have  derived  the  name  of  table-le^^nds.  They 
may  also  descend  to  the  lowlands  by  gradual  slopes,  or 
successive  terraces.  Table-lands  are  intimately  associated 
with  mountains,  and  frequently  serve  as  platforms  from 
which  new  ridges  rise.  Indeed,  the  highest  mountains  of 
the  globe  rise  from  such  regions,  and  many  of  the  noblest 
rivers  gather  thence  their  far-fetched  waters. 

EUROPE.  —  Compared  with  the  other  continents, 
Europe  has  no  table-lands  of  great  extent  or  elevation. 
Its  most  remarkable  one  is  that  of  Spain,  which  occupies 
an  area  of  93,000  square  miles,  or  more  than  half  the 
peninsula,  and  has  a  mean  elevation  of  2200  feet.  There 
are  also  the  plateaux  of  Switzerland,  with  Bavaria  and 
Bohemia,  of  much  inferior  elevation. 

ASIA. — The  table-lands  of  Asia  occupy  ^/^  of  the  entire 
continent.  That  gigantic  mass  of  high  land,  which  forms 
the  gii'dle  of  the  Old  World,  extends  through  Asia  a  dis- 
tance of  6000  miles,  and  is  2000  miles  broad  at  its  east- 
ern extremity,  700  to  1000  in  the  middle,  and  somewhat 
narrower  towards  the  Meditei-ranean.  It  largely  expands 
into  broad  and  lofty  table-lands,  traversed  and  supported 
by  colossal  mountains.  These  table-lands  consist  of  two 
great  divisions, — viz.,  (1)  The  Eastern  Plateau,  or  Cen- 
tral Asia ;  and  (2)  the  Western  Plateau,  united  to  the 
Eastern  by  the  great  mountain-isthmus  of  the  Hindoo 
Koosh. 

Central  Asia,  or  High  Asia,  is  the  most  extensive  and 
elevated  table-land  on  the  globe.     Its  marginal  walls  are 


AFRICA.  35 

the  Himalayas,  the  Bolor  Taiijh,  the  Altai  Mountains, 
and  the  Chinese  ]\Iountains,  %vhil.st  it  is  traversed  by  the 
great  Ku-en-lun  and  Thian-shan  ranges.  In  this  area  is 
included  the  great  rainless  sandy  Desert  of  Gobi  ("  naked 
desert"),  or  Shamo  ("sea  of  sand"),  with  an  elevation  of 
3000  feet,  and  an  area  of  400,000  square  miles,  or  twice 
the  size  of  France.  In  the  centre  is  a  district  called  Han- 
Hal  ("  dry  sea"),  150  miles  in  length  by  20  in  breadth, 
consisting  entirely  of  loose  shifting  sands,  and  altogether 
impassable.  In  the  south  is  the  plateau  of  Tibet,  the 
loftiest  inhabited  land  in  the  world,  with  an  elevation  of 
15,000  feet,  equal  to  the  highes-t  summits  of  the  Alps, 
and  rising  in  some  parts  to  17,000  feet.  A  portion  of 
this  vast  tract  (the  table-land  of  Pamir),  near  the  source 
of  the  River  Oxus,  called  in  the  native  language  Bam-i- 
Duniah,  the  ''  Roof  of  the  World,"  forms  the  highest 
watershed  on  the  globe,  and  is  the  great  centre  from 
which  radiate  all  the  great  mountain  chains  and  largest 
rivers  of  Asia, 

South-west  from  Central  Asia  extend  in  succession 
the  gi-eat  table-lands  of  Iran,  or  Persia,  Arabia,  and  the 
Sahara,  or  Great  Desert,  in  Africa.  These,  along  with 
the  table-lands  of  Central  Asia,  belong  to  the  same 
vast  belt  of  arid,  sandy  rainless  country,  destitute  of 
streams  and  vegetation,  which  extends  over  more  than 
120'  of  longitude  and  17'  of  latitude,  or  about  5,000,000 
square  miles.  Apart  from  these  are  the  plateaux  of 
Armenia  in  ^yestenl  Asia,  and  the  Deccan  in  the  Indian 
Peninsula, 

AFRICA. — Africa  presents  so  great  a  mass  of  elevated 
land  that  it  has  been  compared  to  an  inverted  pudding- 
dish.  Under  the  Equator  itself  the  country  is  so  elevated 
as  to  enjoy  all  the  advantages  of  a  temperate  climate.  All 
the  southern  half  strongly  resembles  the  Deccan  -svith  its 
triangular  elevated  platform  flanked  by  long  mountain 
ransres,  and  descends  to  the  south  in  a  succession  of  ter- 
race-plains,  called  Karroos. 

The  Sahara,  or  Great  Desert,  in  the  north  of  Africa, 


36  PHYSICAL   GEOGRAPHY. 

is  partly  lowland  and  partly  upland  :  in  some  portions  it 
is  low  and  flat,  especially  in  the  west ;  in  others,  it  is 
Baid  to  sink  below  sea-level ;  but  it  consists  for  the  most 
part  of  bare  broad  plateaux  of  1000  to  3000  feet  in 
height.  It  is  the  most  extensive  sterile  tract  of  the  globe, 
having  an  area  equal  to  that  of  the  Mediterranean.  It 
presents  a  vast  expanse  of  burning  sands,  rocks,  or  loose 
shingle,  with  here  and  there  brackish  lakes  or  springs, 
and  the  ground  incrusted  with  salt,  whose  particles  flash 
in  the  sun  like  diamonds.  Without  stream,  rain,  or  dew, 
it  possesses  no  vestige  of  animal  or  vegetable  life,  save 
where,  at  distant  intervals,  some  low-lying  spring  gives 
birth  to  a  patch  or  islet  of  vegetation,  called  an  oasis. 
Such  favoured  spots  maybe  descried  afar  over  the  arid  waste 
by  their  clumps  of  date-palms,  ferns,  and  acacias,  and  they 
aflbrd  a  welcome  resting-i:)lace  to  the  fainting  caravan. 
Like  the  mariner  at  sea,  the  traveller  guides  his  course 
by  the  compass,  or  the  stars,  across  this  "  ocean  without 
water,"  not  in  a  direct  line,  but  to  the  nearest  oasis. 
Without  the  fountains  of  the  oasis,  indeed,  to  recruit  his 
exhausted  skin-bottles,  and  without  the  camel,  "  the  ship 
of  the  desert,"  to  transport  him,  this  vast  region  would 
be  quite  impenetrable  to  man.  But  not  unfrequently  the 
party  of  the  caravan  fall  victims  to  the  deadly  blast  of 
the  simoom,  or  sink,  bafiied  and  bewildered,  beneath  the 
drifting  sands. 

"On  the  interminable  sands  and  rocks  of  these  deserts  no 
animal — no  insect — breaks  the  dead  silence ;  not  a  tree  nor  a 
shrub  is  to  be  seen  in  this  land  without  a  shadow.  In  the  glare 
of  noon  the  air  quivers  with  the  heat  reflected  from  the  red  sand, 
and  in  the  night  it  is  chilled  under  a  dear  sky  sparkling  with  its 
host  of  stars.  Strangely  but  beautifully  contrasted  with  these 
scorched  solitudes  is  the  narrow  valley  of  the  Nile,  threading 
the  desert  for  1000  miles  in  emerald  green,  with  its  blue  waters 
foaming  with  rapids  among  wild  rocks,  or  quietly  spreading  in  a 
calm  stream,  amidst  fields  of  corn  and  the  august  monuments  of 
past  ages." — Mrs.  Somerville's  Physical  Geography. 

NORTH  AMERICA.— The  Table-Land  of  Mexico, 
though  not  the  highest,  is  by  far  the  most  unbroken  on 


SOUTH    AMERICA. 


37 


tlie  face  of  the  earth.  It  is  IGOO  miles  in  lengtli  from 
north  to  soiith,  being  a  distance  as  great  as  from  the 
north  of  Scotland  to  Gibraltar,  with  a  width  of  3 GO  in 
the  latitude  of  the  capital.  The  country  rises  abruptly 
from  both  shores,  but  less  so  from  the  Pacific,  and  its 
whole  mass  is  raised  into  the  air  to  a  medium  height  of 
7000  feet.  It  seems  like  a  flattening  and  broadening 
of  the  £n'eat  meridional  chains  of  the  Americas.  Its  sur- 
face  is  almost  as  level  as  the  ocean,  save  where  volcanic 
cones  shoot  up  from  its  expanse.  The  city  of  Mexico 
stands  in  the  midst  of  a  gi-and  volcanic  circuit  of  moun- 
tains with  snowy  flanks  and  blazing  crests. 


Fret. 

25,00'i 

20,000 

15,000 

10,000 

6,000 


i 


VoL  Popocatepetl 


j--^.     Vol.  Citlaltepetl. 


SECTION  OF  THE  PLATEAU   OF  MEXICO. 

SOUTH  AMERICA.— The  Plateau  of  Bolivia,  or  Upper 
Peru,  situated  between  the  two  Cordilleras,  or  main 
chains  of  the  Andes,  at  an  altitude  of  12,900  feet  (about 
2i-  miles),  has  an  area  of  150,000  square  miles,  or  three 
times  the  size  of  England.  It  is  bounded  by  the  highest 
summits  of  the  Andes,  rising  to  nearly  double  its  own 
height ;  its  Lake  of  Titicaca  is  twenty  times  the  size  of 
the  Lake  of  Geneva ;  its  valleys  are  rich  and  fertile ; 
villages  are  situated,  and  mines  of  silver  worked,  at 
heights  as  great  as  the  Peak  of  Tenerifle  or  Mont  Blanc  j 


53 


PHYSICAL   GEOGRAPItY. 


it  also  possesses  great  and  populous  cities,  and  many 
traces  of  the  power  and  civilisation  of  its  ancient  inhabit- 
ants. The  Plateau  of  Quito,  200  miles  long  and  30 
wide,   and  immediately  under  the  Equator,  is  9600  feet 


Viil.  Acoucacua. 


£-3  Vol.  Arequipa, 

j\         Guilalieri 


-     5,000 


SECTION    OF  THE  PLATEAU   OF  BOLIVIA. 

(or  nearly  2  miles)  above  the  level  of  the  sea.  The 
city  of  Quito  itself,  with  its  70,000  inhabitants,  enjoys 
the  magnificent  spectacle  of  eleven  nevadoes,  or  snow-clad 
mountains,  rising  from  amid  verdant  hills  around  the 
city,  some  of  them  not  unfrequently  tipped  with  smoke 
and  flame. 

Principal  Plateaux. 


Plateau, 

PosiTiox. 

Akea. 

Mean  Height. 

Spanisli  Plateau 

EUROPE. 

Central  Spain, 

Between  Lake  of 
Geneva  &  Lake 
Constance, 

South  of  Germany, 

N.W.  of  Austria,... 

93,000  sq.m 
[  6,000    „ 

30,000    „ 
20,000    „ 

2,000  to   3,000  ft. 

1,350  to   2,000,, 

1,500  to    2,000,, 
900  to   1,500,, 

Plateau  of  Switzerland,  ■< 
Bavaria 

Bohemia, 

LOWLAKD    PLAINS. 


39 


PniNCiPAL  Platilvux — continued. 


Plateau. 


Position. 


Area. 


Mean  IIeigut. 


Eastern  riateau, 

cuiaiirisiiig — 

Gobi,  or  tjhaiuo 

Tibet, 

Valley  of  Caslimerc, 

Western  Plateau 

comprising — 

Iran, 

Armenia, 

Anatolia, 

Arabian  Plateau, 

The  Deccan, 


ASIA- 
Central  Asia, ... 


7,600,000sq.m.  15,000  to  17,000  ft. 


N.W.  of  India,. 


Sahara,  or  Great  Desert, 
Plateau  of  Aniluua, . . 


South  Central  Africa,...  -j 

Kalahari  Desert, 

Great  Karroo, \ 


Labrador, 

Great  Western  Plateau, 

Anahuac,  

Guatimala,  


Plateau  of  Quito,..., 
Plateau  of  Bulivia, 
Plateau  of  Brazil,  . . 


Persia  &  Afghan- 
istan,  

S.E.  of  Black  Sea, 

AsiaMinor, 

Central  Arabia 

Southern  India,,.. 


400,000  „ 

1(30,000  „ 

25,000  „ 

1,700,000  ,, 


300,000  ,, 
70,000  „ 
200,000  „ 
700,000  „ 
250,000  „  ? 


AFRIC.V. 

Xorthern  Africa,..  3000x1000  m. 

Abyssinia 

from  5°  N.  Lat, 

Southwards, .... 
N.  of  Cape  Colony, 
N.    of    Nieuveld't 

^lountains, 


236,000  sq.ro, 
200  X  50  m. 


NORTH  AMERICA. 

E.  of  Brit.  America, I  420,000  sq.m. 
From  Rocky  Mts. ,  )         , 

to  Pacific  Range,  f 
Central  Mexico, ...  1,600x360  m. 
Central  America,..'  ? 


SOUTH  AMERICA. 

Andes  of  Ecuador, 
Andes  of  Bolivia,.. 
Interior  of  Brazil,. 


6,000  sq.  in. 
150,000     „ 
1,500,000  „ 


4,000  to    6,000  „ 

10,000  to  15,000,, 

5,500  to    6,000  ,, 

4,000  to    7,000,, 


3,000  to    6,000,, 

7,000  „ 

3,000  „ 

3,000  to    6,000,, 

1,400  to    3,000,, 


1,000  to 
6,000  to 


2,000  to 


2,000  to 


3,000  ,, 
8,000  „ 

3,000  „? 
3,600  „ 

2,000  „ 


2,000  „ 

5,000  „ 

7,000  „ 
5,000  „ 


9,600  ,, 

12,900  „ 

8,000,, 


LOWLAND  PLAINS. 

14.  Old  World. — Tliat  great  zone  of  high  land  which 
extends  from  the  Atlantic  to  the  Pacific,  divides  the  Old 
World  into  two  verv  dilTerent  regions.  That  to  the  south 
of  it  is,  with  isolated  exceptions,  high  and  mountainous ; 
that  to  the  north  forms  the  Great  Northern  Plain,  ^vhich 
stretches  fi'om  the  German  Ocean  eastwards  to  Behriug's 


40  PHYSICAL   GEOGRAPHY. 

Straits,  intciTupted,  and  that  only  partially,  by  the  trans- 
verse range  of  the  Urals.  "  The  traveller  may  cross  the 
Ancient  World  for  a  distance  of  more  than  6000  miles 
without  encountering  an  eminence  of  more  than  a'  few- 
hundred  feet  in  height."  It  extends  over  190°  of  longi- 
tude, and  includes  an  area  of  nearly  6  millions  of  square 
miles,  Y2  larger  than  Europe,  or  nearly  Y3  of  both  Europe 
and  Asia.  The  European  section  of  this  vast  expanse 
is  divided  into  the  Germanic  Plain  in  the  west,  and 
the  Sarmatian  Plain  in  the  east;  while  in  Asia  it 
is  occupied  by  the  Steppes  of  Kirghiz,  Ischim,  and 
Baraba,  in  the  south-west,  and  the  Siberian  Plain  in 
the  north. 

Great  Plain  of  Europe. — From  the  Carpathians  to 
the  Urals,  a  distance  of  1500  miles,  there  is  almost  a 
dead  level.  In  the  west  of  Russia,  rivers  that  flow 
north  and  south  to  the  Baltic  and  Black  Seas  take 
their  rise  under  the  shadow  of  the  same  tree ;  when  in 
flood,  they  convert  the  swamps  around  their  source 
into  one  continuous  lake,  so  that  the  traveller  might 
pass  by  boat,  without  interruption,  from  the  Baltic  to 
the  Euxine.  One  river,  the  Pripet,  creeps  along  to  the 
Dnieper  through  a  swamp  as  long  as  England.  On  the 
west,  the  polders  and  morasses  of  Holland  are  preserved 
from  the  overflow  of  the  sea  by  means  of  dykes;  and  in  the 
south-east,  on  the  shores  of  the  Caspian,  the  land  dips  83 
feet  below  the  ocean  level.  A  strong  wind  from  the  north 
drives  the  waves  of  the  Baltic  into  the  mouth  of  the 
Oder,  and  gives  its  waters  a  backward  course  for  30  or 
40  miles.  In  the  Germanic  section  occur  the  mud  flats 
of  Holland,  the  boulder-strewn  sandy  plains  of  Prussia, 
and  the  pastures,  heaths,  and  swamps  of  Denmark  and 
the  northern  sea-board.  In  the  Sarmatian  Plain,  the 
cold  swampy  flats  of  the  north,  and  the  natural  forests 
of  pine  and  fir,  with  the  great  fertile  grain-bearing  tracts 
of  the  middle,  are  succeeded,  in  the  south,  by  the 
steppes. 

Steppes. — These  steppes,  as  their  name  implies,  are 


Secondary  plaiks.  41 

"deserts  without  trees,"  covered  in  the  west  with  long 
coarse  grass  and  gravel,  and  in  the  east  with  saline  de- 
2)osits  as  white  as  hoar-frost.  The  steppes  of  Asia 
present  a  monotonous  dead  level  bounded  by  the  horizon. 
Upon  their  rough  gi^ass  and  shrubs  countless  horses, 
camels,  and  cattle  browse  during  a  brief  season  of  ver- 
dure; but  summer  droughts  convei-t  them  into  parched 
deserts,  and  winter  snows  into  scenes  of  trackless 
desolation.  The  steppes  alone  are  estimated  to  cover 
a  surfiice  of  1,000,000  square  miles. 

Tundras. — Along  the  north  of  Russia  and  Siberia  aro 
low-lying  tundras,  or  eai-thy  peat  mosses,  where  the 
ground  is  perpetually  frozen  to  a  great  depth,  except  for 
a  few  weeks  in  summer,  when  the  surface  is  partially 
thawed. 

Landes  (•'  heaths  ")  are  extensive  tracts  on  the  coast  of 
the  Bay  of  Biscay,  between  the  Gironde  and  the  Pp-enees, 
generally  sandy,  sometimes  marshy,  mostly  covered  with 
heath  and  dwarf  shrubs.  Over  these  grounds  the  natives 
generally  walk  on  stilts. 

Dunes  are  low  sand-hills  which  stretch  along  the  coast 
of  the  Netherlands  and  north  of  France.  They  are  formed 
of  drifted  sands,  and  effectually  protect  the  low-l^ing 
country  from  the  overflow  of  the  tides.  They  are  pai-tially 
covered  with  gi-ass  and  heath,  and  are  unfit  for  pasturage 
or  cultivation. 

Polders  are  flat  tracts  in  Holland  below  the  level  of 
the  sea  or  nearest  river,  such  as  a  lake  or  morass  which 
has  been  drained  and  brought  imder  cultivation.  They 
are  protected  from  inundation  by  embankments  called 
di/l-es.     Similar  to  these  are  the  Fens  of  England. 

Secondary  Plains.  —  Of  the  secondary  plains  of  the 
Old  World,  the  most  important  are  those  of  the  Middle 
and  Lower  Danube ;  the  fertile  Valley  of  the  Po,  iu 
Northern  Italy;  the  gi-eat  river  Plain  of  China,  ccpial 
in  area  to  the  whole  of  France;  the  Plains  of  Hindostan, 
stretching  from  the  Himalayas  to  the  Deccan  along  tlia 
north  of  India;  and  the  historic  Plains  of  Mesopotamia 


42  PHYSICAL   GEOGRAPliy. 

(between  the  Euphrates  and  the  Tigris),  in  Western  Asia, 
the  seat  of  the  earliest  empii-es.  The  greater  part  of  the 
interior  of  Australia  was  long  believed  to  be  "a  treeless 
uninhabited  desert  of  sand  and  shingle,  probably  the  bed 
of  a  dried-up  sea,  and  all  but  impassable  from  the  want  of 
water ;"  but  recent  explorations  have  materially  modified 
this  opinion.  "  A  large  part  of  the  surface'  is  occupied 
by  extensive  sandy  and  stony  deserts;  elsewhere,  fine 
pasture  and  woodland  are  met  with ;  while,  in  many 
places,  the  country  is  well-watered,  with  undulating 
hills." 

15.  New  World — But  great  plains  are  the  most  charac- 
teristic feature  of  the  New  World.  A  great  Central  Plain 
may  be  said  to  extend  from  the  Arctic  Ocean  to  Tierra 
del  Fuego,  although  broken  by  the  Gulf  of  Mexico  and 
the  Caribbean  Sea.  Whilst  its  extremities,  more  than 
9000  miles  apart,  are  charged  with  the  Arctic  and  An- 
tarctic snows,  its  middle  is  overshadowed  by  tropical 
palms.  In  North  America  it  is  contained  on  the  west 
and  east  by  the  Rocky  Mountains  and  the  Alleghanies, 
and  in  the  southern  continent  by  the  Andes  and  tlio 
Cordilleras  of  Brazil. 

Prairies. — In  North  America,  rising  ground  of  no 
grea.t  elevation  along  the  50th  parallel,  turns  the  water 
to  the  north  towards  the  Arctic  Ocean,  and  to  the  south 
by  the  great  basin  of  the  Mississippi.  This  latter  great 
tract,  comprising  an  area  of  3,000,000  square  miles,  has 
been  characterized  by  Humboldt  as  "  an  almost  con- 
tinuous region  of  savannahs  and  prairies."  The  praiiies 
on  both  sides  of  the  Mississij)pi,  but  chiefly  on  the  west, 
are  vast  natural  "  meadows," — most  of  them  level  or  of 
a  rolling  or  undulating  surface,  without  trees  or  water, 
and  covered  with  luxuriant  grass  and  flowers.  On  the 
wide  plains  roam  countless  herds  of  wild  horses,  bisons, 
and  deer.  At  the  base  of  the  Bocky  Mountains,  and  near 
the  sources  of  the  Missouri,  is  the  American  Desert,  a 
vast  tract  of  sand  and  gravel;  but  eastwards  towards 
the   Allegliany  Mountains   the   plain   is    covered   with 


PAMPAS.  43 

immense  natural  forests,  many  of  them  still  untouched 
by  tlie  woodman's  axe.  Along  the  Gulf  of  Mexico, 
and  far  into  the  interior,  are  the  Pine-barrens,  extensive 
monotonous  tracts  of  sand,  clothed  with  gigantic  pine- 
trees. 

In  South  America  the  Central  Plain  is  divided  into 
three  distinctive  and  well-marked  river  plains,  viz.,  those 
of  the  Orinoco,  the  Amazon,  and  the  La  Plata. 

(1)  Llanos. — The  first  is  the  region  of  the  Llanos,  or 
grassy  flats,  extending  over  160,000  square  miles.  Over 
hundreds  of  miles  the  surface-level  often  does  not  vary  a 
single  foot,  and  in  the  wet  season  it  is  overflowed  for 
hundreds  of  square  miles.  Shortly  after,  they  become 
so  richly  clothed  with  verdure  as  to  be  called  in  the 
native  language,  "the  sea  of  grass;"  but  in  the  suc- 
ceeding drought  the  grass  crumbles  into  dust,  and  tlie 
luxuriant  tropical  vegetation,  parched  and  withered,  is 
often  consumed  like  tinder  in  one  wide  wasting  con- 
flagration. 

(2)  Selvas. — The  second,  or  j^lain  of  the  Amazon,  is  the 
largest  river  basin  in  the  world,  being  1,500,000  square 
miles  in  area  {^ I ^  of  Eurojiean  Russia,  or  seven  times 
the  size  of  France).  It  is  distinguished  by  its  Selvas 
("  forests")  covered  v/ith  the  rankest  forest-gro^vths,  so 
dense  that  they  can  be  threaded  only  by  the  river-courses. 
At  the  annual  inundation  the  natives  take  to  the  trees,  and 
form  villages  among  the  interlacing  branches.  "  Were 
it  not  for  intervening  rivers,  the  monkeys,  almost  the 
only  inhabitants,  might  pass  along  the  tops  of  the 
trees  for  several  hundreds  of  miles  without  touching  the 
ground." 

(3)  Pampas. — Tlie  third  division  is  the  Pampas  (''plains") 
of  the  La  Plata  and  is  880,000  square  miles  in  extent. 
It  consists  chiefly  of  rich  alluvial  soil,  destitute  of  trees, 
with  grassy  pastures  and  immense  flats,  covered  at  one 
season  with  gigantic  thistles,  some  of  them  ten  feet  high; 
at  another,  with  the  richest  clover.  Troops  of  wild  horses 
and  cattle  scour  the  plains,  or  browse,  almost  concojiled. 


44 


PHYSICAL   GEOGRAPHY. 


among  the  luxuriant  thistles  and  other  herbage.  Bounded 
on  the  east  by  the  River  Paraguay  is  the  immense  arid 
sandy  desert  of  El  Gran  Chaco  ;  along  the  west,  near  the 
base  of  the  Andes,  is  a  great  salt  desert  bearing  the  name 
of  Las  Salinas;  and  a  desert  of  shingle,  700  miles  in 
length,  consisting  of  five  great  terraces  sloping  eastwards, 
extends  through  eastern  Pataijonia. 

16.  Uses  of  Plains. — AVhilst  mountains  and  plateaux 
play  a  most  important  part  in  the  physical  economy  of 
nature,  the  plains,  from  their  milder  climate,  fertile  soil, 
and  well-watered  surface,  have  been  the  chief  nurseries  of 
animal  and  vegetable  life,  the  chief  seats  of  population, 
and  the  great  theatres  of  industry  and  civilization.  In 
spite  of  immense  wastes  of  barren  sands,  salt,  and  shingle 
that  cumber  so  much  of  the  earth,*  they  have  formed 
from  the  earliest  ages  the  pasture-lands  of  roving  tribes; 
or  the  busy  plough  of  the  husbandman  has  made  them 
the  rich  granaries  of  the  globe. 


Peixcipal  Plains. 


\ 


Plain. 


Position, 


Area. 


The  Great  Plain, | 

Plain  of  Middle  Danube,  ... 

Plain  of  Lower  Danube, 

Plain   of    Lombardy,    or ) 
Valley  of  the  Po, | 

Plain  of  France, ■< 

The  Great  Northern  Plain, 

Plain  of  Turkestan, 

Plain  of  Mesopotamia,  

Plains  of  Hindostan, 

Plain  of  China, 

Plains  of  Indo-China, 


EUROPE. 

in  the  Centre  and  East  of 

Europe, 

in  Hungary, 

in  North-East  of  Turkey,... 

in  the  North  of  Italy, 

in  the  North- West  and  West 
of  France, 

ASIA. 

Siberia 

East  of  the  Caspian, 

S.E.  of  Turkey  in  Asia,... 
in  the  North  of  India,  ...., 
Middle  of  China  Proper,.. 
Farther  India, 


12,500,000  sq.  m. 


25,000 
60,000 

40,000 


5,000,000 

1,000,000 

165,000 

210,000 

9 


II 


*  Deserts  are  estimated  to  occupy  five  or  six  millions  of  square 
miles,  i.e.,  about  one-half  larger  than  Europe,  or  40  to  50  times 
the  size  of  the  British  Isles. 


VALLEYS. 


45 


Principal  Tlai'SS— continued. 


Plain-. 


Position. 


AUEi 


AFRICA. 
Great  Central  Plain, J   South  of  Sahara, J 


Great  Central  Plain, 
The  Atlantic  Plain,  . 


NORTH  AMERICA, 

from  Arctic  Ocean  to  Gulf 

of  Mexico, 

(     between  the  Appalachians 
^      and  Atlantic, 


I  3,000,000  sq.  m. 
j-    767,000      „ 


SOUTH  A^IERIC.L 


Great  Central  Plain, 


f 

comprising, 
Tlie  Llanos  of  the  Orinoco, 
The  Selvas  of  the  Amazon, 
The  Pampas  of  La  Plata, 
Desert  of  Patagonia, 


from  the  Caribbean  Sea  to 
the  Rio  de  la  Plata, 


in  the  North 

in  the  Middle, 

in  the  South 

in  the  East  of  Patagonia,. 


ICO.OOO 

1,500,000 

880,000 

140,000 


17.  Valleys. — Yulleys  are  gi'eat  natural  depressions  on 
the  earth's  surface,  generally  occupied  by  streams,  from 
which  they  receive  their  names.  They  are  of  different 
characters,  accoi'ding  as  they  occur  in  tlie  upper  or  tlio 
lower  course  of  rivers,  or  on  the  wide  expanse  of  table- 
lands. 

(1)  In  the  first  case  they  are  closely  associated  with  moun- 
tains, being  bounded  by  their  precipitous  sides,  high  above 
sea-level,  and  they  contain  the  mountain  torrent  which 
receives  the  product  of  the  springs,  rains,  or  snows  of 
the  adjoining  heights.  The  scenery  is  generally  grand 
and  picturesque.  The  stream  is  intercepted  by  natural 
obstacles  so  as  to  form  lakes,  or  foams  in  cascades  and 
waterfalls  over  the  rugged  and  precipitous  bottom.  Many 
of  them  are  valleys  of  erosion,  owing  their  existence  to 
the  ceaseless  action  of  running  water,  wearing  and  under- 
mining the  rocks,  carrying  the  debris  farther  down  the 
valley,  and  thus  ever  deepening  their  channels  as  they 
flow.  Others  are  valleys  of  fracture  or  fault,  formed 
originally  when  the  mountain-masses  were  upheaved, 
when  the  rocks  were  cracked  and  bi'oken,  and  the  two 


46  PHYSICAL    GEOGRArilY. 

sides  of  tlie  fissure  deposited  apart,  and  pei-liaps  at 
dilFerent  levels.  The  clefts  or  crevices  thus  caused  became 
afterwards  the  beds  of  running  streams  gathered  from  the 
mountain  sides.  These  valleys  may  be  either  longitudinal 
or  transverse,  according  as  they  run  parallel  with  the 
length  of  the  main  mountain  chain,  or  cut  it  at  right 
angles.  By  means  of  the  transverse  valleys,  often  of 
great  depth,  as  in  the  Alp)s  and  Himalayas,  access  is 
afforded  to  those  mountain-passes  which  form  the  con- 
necting links  between  countries  on  opposite  sides  of  great 
mountain-barriers. 

(2)  The  second  case  occurs  in  the  lower  river-course, 
where  the  narrow  glen  or  ravine  widens  out  into  open 
plain,  generally  before  the  river  approaches  the  sea,  when 
its  confines  are  ill-defined,  and  it  differs  little  except  in 
name  from  the  broad  open  plain  of  the  country  around. 
Such  are  the  valleys  of  the  Ganges,  the  Mississippi,  the 
Amazon,  and  other  large  rivers.  The  other  belongs  to 
almost  all  streams  of  mountain  origin. 

(3)  The  valleys  of  table-lands  are  generally  deep  clefts  or 
gorges,  cutting  abruptly  the  mountains  or  plateaux  they 
traverse.  Their  sides  are  precipitous,  although  often 
miles  apart,  the  scenery  is  often  very  grand  and  striking, 
and  they  interfere  materially  with  communication  between 
the  opposite  banks.  Such  are  the  river-valleys  of  Sj^ain, 
the  course  of  the  Zambesi  in  South  Central  Africa,  the 
Canons  of  the  Kio  Colorado  in  North  America,  and  the 
plains  of  Western  Tibet. 

MEAN  ELEVATION  OF  THE  CONTINENTS. 

Thus,  on  a  general  review  of  the  land-suiface,  we  may 
observe  that  in  the  Old  World  onountains  and  plateaux 
jyredominate —  5/?  of  Asia  and  V4  of  Europe  being  thus 
occupied.  The  New  World,  on  the  other  hand,  is  the 
iDorld  of  plains,  which  form  ^jz  of  its  surface.  All  the 
mountains,  and  more  especially  the  table-lands,  tend  to 
raise  the  general  level,  while  the  plains  have  the  import- 


EXEUCISES. 


47 


r 


ant  cfiect  of  largely  reducing  it.  If  the  whole  mass  of 
the  Pyrenees  were  reduced  to  powder  and  strewn  equally 
over  the  surface  of  Europe,  it  would  raise  the  general 
level  by  G  feet;  the  Alps  would  raise  it  22  feet;  whilst 
/  the  plateau  of  Spain,  if  treated  in  a  similar  manner,  would 
heiirhten  the  surface  76  feet.  If  all  the  mountains  and 
table-lands  of  the  globe  were  to  be  thus  broken  up  and 
spread  out  over  theii*  respective  continents,  it  has  been 
calculated  that  the  mean  elevation  of  the  continents  would 
be  as  follows : — Europe,  670  feet;  Asia,  1150  feet;  Africa, 
900  feet;  Noi-th  America,  750  feet;  and  South  America, 
1130  feet;  the  whole  land  of  the  globe,  nearly  1000  feet. 


\ 


Ft 
IIOO 

ICOO 

600 

400 

800 


5 


Asia n;9. 

S.  America,    1130. 


I 


-  Africa, 9C0. 

"■N.  America,    750. 
Europe, G70. 


'  The  whole  T,sr.d 
,  of  the  Glob* 
t     1000  fe«t. 


Seft-Lerel 


Comparative  View  of  the  Mkan'  Elevation  of  the  Continents. 


EXEPtCISES. 

1.  AMiich  continent  appears  to  present  an  exception  to  the 
first  law  of  vertical  arrangement  ?  Let  the  pupil  draw  a  section 
of  Europe  from  the  Baltic  to  the  Plain  of  Northern  Italy. 
Point  out  and  name  the  chief  mountain  chains  in  both  the  Old 
and  the  New  World  that  do  not  follow  the  direction  of  the  con- 
tinents. Pleasure  the  great  mountain  axis  of  the  Old  World  and 
the  New.  ^^'here  is  it  most  remote  from  the  ocean,  and  how  far  ? 
Where  is  this  axis  most  interrupted,  and  where  is  it  broken  by 
the  sea?  Which  African  chain  belongs  to  it,  and  how  is  it 
detached  fi-om  it  ?  Which  is  the  central  mountain  system  of 
Europe  ?  Which  are  entirely  unconnected  with  it  ?  Give  the 
chains   that  occupy  the  leading  peninsulas  and  islauda  of  the 


48  PHYSICAL   GEOGRAPHY. 

world.  Give  tlie  islands  wliicli  may  be  considered  as  prolonga- 
tions of  the  Maritime  or  Western  Alps,  the  Apennines,  Mount 
Atlas,  the  Urals,  the  Scandinavian  Mountains.  Which  import- 
ant mountain  chain  is  nearly  half-way  from  the  Equator  to 
the  Pole?  Which  European  peninsula  is  not  mountainous,  and 
how  does  it  differ  from  the  others  ? 

2.  What  is  the  central  chain  of  Western  Asia  ?  What  chains 
radiate  from  it,  and  in  what  directions  ?  What  is  the  chain  of 
Central  Asia  from  which  all  the  others  may  be  said  to  radiate  ? 
Which  chain  is  half-way  along  the  great  mountain  axis  of  the 
Old  World  ?  Which  chain  connects  the  Western  and  the  Central 
system  of  Asia  ?  Arrange  in  tabular  form  the  culminating  points 
of  the  six  great  land  divisions  of  the  globe  with  their  respective 
mountain  ranges.  Give  a  comparative  view  of  their  heights,  by 
a  scale  or  otherwise.  Keduce  the  heights  to  miles,  and  com- 
pare them  with  that  of  some  height  with  which  you  are  familiar. 
Lay  down  on  a  map  the  leading  mountain  ranges  in  the  world 
and  their  culminating  points. 

3.  Which  of  the  continents  may  be  considered  as  forming  one 
great  plateau  ?  Which  contains  the  highest  and  largest  plateaux  ? 
Which  the  fewest  ?  Name  the  several  plateaux  connected  with 
the  Himalayas,  the  Alps,  the  Rocky  Mountains,  the  Andes.  Name 
those  in  peninsulas,  and  state  how  these  peninsulas  resemble  each 
other  in  respect  of  outline.  What  mountain  chains  support  the 
table-lands  of  Iran  ?  of  Armenia  ?  of  Anatolia  ?  the  I)eccan  ? 
Spain?  South  Central  Africa?  Which  plateaux  are  tmversed  by 
mountains  ?  Point  out  the  greatest  series  of  table-lauds  on  the 
globe.  How  are  they  separated  from  each  other?  In  what 
respect  do  they  resemble  each  other  ?  Write  out,  from  memory, 
a  descriptive  account  of  the  Desert  of  Sahara.  Arrange  the  prin- 
cipal table-lands  in  the  older  of  their  heights.  Compare  their 
mean  elevations  with  each  other,  and  with  some  well-known 
height.    Compare  their  areas  with  that  of  the  British  Isles. 

4.  How  are  the  lowlands  of  Asia  situated  relatively  to  the  whole 
continent?  How  do  those  of  the  New  World  differ  from  them  in 
relative  position?  How  do  the  great  lowlands  and  plateaux  of 
the  Old  World  lie  respectively  from  the  great  mountain  axis  ? 
Name  the  countries  embraced  in  the  Great  Northern  Plain  of  the 
Old  World  and  in  the  Great  Central  Plain  of  the  New  World. 
What  feature  in  common  have  the  secondary  plains  of  the  Old 
World?  Wliat  rivers  traverse  these  plains?  What  mountains 
bound  them?  Which  European  plains  form  prolonged  portions 
of  the  Great  Plain?  Which  Asiatic  plains  have  corresponding 
relative  positions  to  the  Plains  of  Lombardy  and  the  Lower 
Danube?  Write  out  from  memory  a  descriptive  account  of  the 
Great  Northern  Plain,  and  of  the  Great  Central  Plain.  ComjDare 
the  areas  of  the  principal  plains  with  that  of  the  British  Isles. 


THE  WATERS  OF  THE  OCEAN.  49 


CHAPTEr.  III. 
THE  WATERS  OF  THE  OCEAN. 

Divisions— Dimensions  of  the  Oceans— Configuration— Mutual 
Eelations  of  Land  and  Water  — Depth  —  Quantity  —  Tem- 
perature —  Sal  tness— Colour  —  Waves — Tides  —  Tide- Waves 
— Currents — Causes  of  Currents — Equatorial  Current — The 
Gulf  Stream—  The  Arctic  Current— Uses  of  Currents— Table 
of  Ocean  Currents. 

18.  Divisions. — Athough  the  ^valcrs  which  engirdle 
the  earth  and  till  up  its  vast  abysses,  form  but  one  con- 
tinuous expanse,  having  no  detached  portions  like  the 
land,  they  have  been,  for  convenience'  sake,  divided  into 
Five  Great  Basins,  called  Oceans.  This  division,  as  well 
as  their  configuration,  is  dependent  upon  the  arrange- 
ment and  forms  of  the  gi-eat  land-masses.  Two,  the 
Pacific  *  and  the  Atlantic,  t  extend  between  the  great 
Eastern  and  Western  Continents;  two,  the  Arctic  and 
Antarctic  (or  Northern  and  Southern),  are  polar;  while 
the  Indian  Ocean,  cut  oil  from  the  Pacific  by  Australasia, 
may  be  styled  equatorial.  A  certain  correspondence  in 
the  relative  positions,  forms,  and  areas  of  the  land  and 
water  of  the  globe  may  be  observed  by  comparing — 

(1)  The  Pacific  and  the  Old  World  ; 

(2)  The  Atlantic  and  the  New  World. 

(3)  The  Indian  Ocean  and  Australia. 

As  the  Old  World  is  about  twice  the  size  of  the  New,  so 
the  Pacific  is  twice  the  size  of  the  Atlantic;  the  Atlantic 
and  the  New  World  are  both  long  and  comparatively 

*  The  Pacific  was  so  called  by  its  first  explorer,  Magellan,  in 
1520,  from  the  calm  weather  he  enjoyed  on  his  first  voyage. 

fThe  Atlantic  received  its  name  from  the  Atlas  Mountains, 
in  Barbary,  which  formed  a  prominent  landmark  to  the  early 
navigators  of  that  ocean,  and  seemed  as  if  presiding  over  ita 
waters, 

23s  D 


50 


PHYSICAL   GEOGRAPHY. 


^ 

I 


narrow,  having  their  greatest  extension  from  north  to 
south.  And  just  as  the  continents,  as  a  general  feature, 
narrow  to  a  point  on  the  south,  so  the  oceans,  fitting  in 
with  the  configuration  of  the  land,  are  broad  and  open  at 
the  south,  and  narrow  towards  the  north. 

Table  of  Dimensions  of  the  Oceans. 


Pacificjt 

Greatest 
Lcugth. 

Greatest 
Breadth. 

Areas. 

9,000  MHes. 
9,000     „ 
4,500      ,, 
2,400      „ 
3,2064-    „ 

12,000  Miles,  i  72.000.000  So.  M.  1 

Atlantic, 

Indian  Ocean, . 
Arctic, 

•4,100      „ 
4,500      „ 
2,400      „ 
3,2601    „• 

35,000,000      „ 
25,000,000      „ 
5,000,000      „     ? 

• 

Antarctic, 

19.  Configuration.  —  The  oceans  have  their  charac- 
teristic forms  and  features  as  well  as  the  land  : — 

(1)  The  Pacific  Ocean  presents  the  appearance  of  a 
rude  oval,  but  open  on  the  south,  where  it  merges  into 
the  Southern  Ocean.  Its  eastern  shore  presents  the  most 
extended  line  of  unbroken  coast  in  the  world,  having 
no  considerable  opening  save  the  Gulf  of  California  and 
the  Bay  of  Panama.  On  the  Asiatic  shore,  however,  it 
is  distinguished  by  five  large  land-locked  seas,  shut  in  by 
peninsulas  and  island  chains :  viz.,  the  Sea  of  Kamtchatka, 
the  Sea  of  Okhotsk,  the  Sea  of  Japan,  the  Yellow  Sea,  and 
the  Chinese  Sea.  In  regard  to  contour,  the  Pacific  is  the 
ocean  of  land-loched  seas.  But  its  most  distinctive  feature 
is  the  numberless  island -forms  that  stud  its  bosom. 
Between  the  two  Tropics,  from  north-west  to  south-east, 
a  distance  of  4000  miles  by  1500  miles  in  width,  extends 
the  vast  island-system  of  Polynesia,  mostly  built  up  from 
the  depths  below  by  the  tiny  coral-insect,  working  iii 
myriads,  and  working  for  ages. 

(2)  The  Indian  Ocean — whilst  itself  assuming  the  form 
of  an  immense  gulf,  Avith  India  at  its  apex  clea^dng  its 

*  The  Pacific,  called  also  the  Great  Ocean,  exceeds  in  area  all 
the  dry  land  of  the  globe,  and  forms  about  one-half  of  its  watery. 


ARCTIC   AND   ANTARCTIC   OCEANS.  51 

noitliern  waters  into  tlie  Bay  of  Bengal  and  the  Arabian 
Sea — sends  tlie  Bed  Sea  and  tlie  Persian  Gulf  far  into 
the  land  on  both  sides  of  the  Arabian  peninsula.  It  has 
been  styled  the  ocean  of  gulfs. 

(3)  The  Atlantic  Ocean  extends  like  a  -winding  channel 
between  the  Old  World  on  the  east  and  the  New  AYorld 
on  the  west,  opening  freely  at  both  ends  into  the  Northern 
and  Southern  Oceans.  The  projections  and  indentations 
of  its  opposite  shores  correspond  to  each  other — the  one 
receding  as  the  other  advances.  It  is  distinguished  by 
the  indentations  of  the  shores  of  its  northern  basin,  while 
those  of  the  south  are  close  and  unbroken.  It  is  the 
ocean  of  inland  seas — having  two  on  the  east,  the  Baltic 
and  the  Llediterranean  (with  its  extensions  into  the  Black 
Sea  and  Sea  of  Azov);  and  two  on  the  west,  Hudson's 
Bay  and  the  Gulf  of  Mexico.  It  has  also  the  land-locked 
seas  of  the  German  Ocean,  the  Caribbean,  and  the  Gulf 
of  St.  La"\\Tence.  Thus  closely  connected  by  its  arms 
with  the  interior  of  the  great  continents,  it  is  the  most 
frecpiented  of  all  the  oceans,  and  has  become  the  great 
highway  of  nations  to  the  civilized  world.  From  the 
Azores  westwards  to  the  Bahamas  extends  the  Sargasso, 
or  Grassy  Sea,  covered  v>-ith  a  kind  of  floating  sea-weed, 
called  "Gulf  weed,"  supposed  to  be  accumulated  by  the 
Gult  Stream.  It  covers  an  area  of  nearly  1,200,000 
square  miles,  nearly  ten  times  the  size  of  the  Briti.^h 
Islands,  and  its  waters  are  almost  stagnant. 

(4)  and  (5)  The  Arctic  and  Antarctic  Oceans  being  so 
much  ice-locked,  are  in  a  gi'eat  measure  unknown  to  us, 
having  hitherto  resisted  all  attempts  to  penetrate  to  either 
pole.  The  neighbourhood  of  the  North  Pole  has  by  some 
been  supposed  to  be  open  sea,  but  the  nearest  approach  to 
it  was  at  a  distance  of  500  miles  (82^  55').  The  skill  and 
enterprise  of  the  jiresent  day  have  burst  the  icy  barrier 
of  the  North- West  Passage  to  India,  which  had  ba-ffled 
the  attempts  of  300  yeai*s;  but  although  thus  ])roved  to 
exist,  the  passage  is  of  no  practical  value,  being  closely 

hliut  up  by  ice.    The  Arctic  or  i  rozen  Ocean  is  almost 


62  PHYSICAL   GEOGRAPHY. 

land-locked,  opening  only  into  the  Atlantic  by  Davis* 
Straits  and  between  Greenland  and  Norway,  and  into  the 
Pacific  at  the  Straits  of  Behring.  It  is  almost  circular, 
being  2400  miles  in  diameter,  and,  so  far  as  known,  its 
surface,  except  near  the  mainland,  is  broken  by  no  land 
save  Greenland,  Nova  Zembla,  and  Spitzbergen.  The 
Antarctic  Ocean  is  still  more  dreary,  boisterous,  and 
inaccessible  than  the  Arctic,  and  it  sends  its  icebergs  ten 
degrees  nearer  the  equator.  Victoria  Land,  the  most 
southern  land  known,  with  its  great  volcanic  peaks, 
Erebus  and  Terror,  and  shores  entirely  destitute  of  vege- 
tation, might  favour  the  idea  of  a  southern  continent. 
But  no  navigator  has  yet  exj^lored  its  scenes  of  eternal 
desolation  nearer  than  78°  10'  south  latitude,  or  800  miles 
from  the  southern  pole. 

r  20.  Mutual  Relations  of  Land  and  Water. — The 
general  distribution  and  leading  outlines  of  the  ter- 
raqueous globe  may  serve  to  indicate  the  wise  and 
beneficent  designs  of  the  Great  Architect.  All  the 
reasons  of  the  present  arrangements  we  cannot  pretend 
to  know,  but  to  state  one  or  two  of  the  more  obvious 
may  here  suffice.  In  primeval  times,  when  man  had 
gained  little  or  no  control  over  wind  and  wave — with 
the  two  great  contments  only  36  miles  apart  at  Behring's 
Straits,  and  with  the  great  stepping-stones  of  the  Aleutian 
Isles  between — the  present  distribution  of  the  land  was 
perhaps  the  most  convenient  for  the  migrations  of  man. 
But  now  that  the  ocean  is  no  longer  dreaded  as  a  disunit- 
ing barrier,  it  is  the  grand  medium  of  intercourse  between 
the  different  regions  of  the  globe.  Its  very  vastness 
favours  the  ease  and  frequency  of  the  intercourse.  Above 
all,  as  we  shall  learn  more  fully  hereafter,  the  ocean  is 
the  great  storehouse  of  warmth,  moisture,  and  winds, 
which  are  there  elaborated  and  sent  forth,  through  the 
mutual  action  of  land  and  water,  to  carry  fertility  and 
beauty  over  the  face  of  the  globe.  Had  the  chief  develop- 
ment of  land  been  in  the  Polar  or  Torrid  Zones,  instead 
of  the  Temperate,  man  could  never  have   reached  his 


DEPin.  53 

present  pitcli  of  civilization ;  he  must  have  remained 
for  ever  the  half-civilized,  shivering  Esquimaux,  or  the 
degraded  sun-burnt  Nec^ro  of  the  Line.  Were  the  relati\-o 
areas,  configurations,  or  positions  of  land  and  sea  to  he 
materially  altered,  the  climate  of  the  globe,  with  all  its 
vegetable  and  animal  forms,  Avould  be  affected,  and  life 
and  vegetation  over  extensive  regions  might  be  succeeded 
by  sterility  and  death. 

21.  Depth. — The  bed  of  the  ocean,  like  the  surface  of 
the  dry  land,  presents  gi'cat  inequalities — being  diversi- 
fied by  jilains,  plateaux,  valleys,  and  mountains  of  very 
varied  dimensions.  As  a  general  law,  low  lands  are 
bordered  by  shallow  seas,  and  high  lands  by  deep  water — 
the  gentle  or  abrupt  slope  of  the  adjacent  shores  being 
continued  underneath  the  waves.  The  gi'eat  plains  of 
Northern  Europe,  Asia,  and  America,  slope  gi-adually 
into  the  shallow  bed  of  the  Arctic  Ocean,  while  the 
abrupt  terminations  of  Africa  and  South  America  dip 
suddenly  into  deep  waters.  A  gi-eat  plateau  at  the 
bottom  of  the  Atlantic  stretches  from  Ireland  to  New- 
foundland (IGOO  miles),  at  a  depth  of  from  1450  to  2424 
fathoms,  or  an  average  depth  of  about  1950  fithoms. 
This  forms  the  bed  of   the  Atlantic  Telegi-ajih  Cables. 

**  The  floor  of  the  Atlantic,  as  determined  by  deep  soundings, 
consists  of  a  series  of  descending  steps,  not  very  closely  resem- 
bling the  form  of  any  of  the  large  tracts  of  land  now  above  the 
sea,  but  having  more  resemblance  to  Africa  than  Europe,  Asia, 
or  America.  Very  broad  and,comparatively  level  terraces  extend 
for  a  certain  distance  beyond  the  existing  shores,  and  are  suc- 
ceeded by  steep  cliffs  dropping  some  9000  feet.  For  a  distance 
of  230  miles  from  the  coast  of  Ireland,  there  is  a  slope  of  only 
about  G  feet  in  a  mile  (one  in  a  thousand).  In  the  next  20  miles 
there  is  a  fall  of  9000  feet  (one  in  twelve),  after  which,  fur  1200 
miles,  there  seems  little  disturbance  of  level.  This  vast  terrace 
is  one  of  several  that  appear  to  characterise  the  bottom  of  the 
great  Atlantic  canal.  iJy  a  succession  of  drops  wc  at  length 
attain  the  greatest  depth,  about  30,000  feet,  which  is  on  the 
American  side  of  the  ocean,  some  distance  south  of  the  great 
bank  of  >s'ewfoundlaud,  and  between  the  30th  and  40th  parallels 
of  latitude.  At  this  depth,  there  is  a  basin-shaped  depression, 
nearly  1000  nules  in  length." — Ansted's  Physical  (Jeograplty, 


54  niYSICAL   GEOGRAPHY. 

Tlie  mean  depth  of  the  ocean  has  been  estimated  at 
21,000  feet,  or  about  4  English  miles,  and  the  extreme 
depth  at  50,000  feet,  or  more  than  9  miles.  The  Atlantic, 
averaging  from  3  to  5  miles,  is  deeper  than  the  Pacific, 
although  40,000  feet  have  been  reached  by  soundings  in 
the  latter;  the  Indian  and  Southern  Oceans  are  from 
4  to  6  miles ;  the  Antarctic  becomes  shallower  towards 
the  Pole;  the  Arctic  is  generally  supposed  to  be  the 
shallowest  of  the  oceans.  The  minor  seas  exhibit  much 
diversity  of  depth. 

22.  Quantity. — The  quantity  of  water  in  the  ocean 
(which  it  is  im230ssible  as  yet  to  estimate  correctly)  is 
always  the  same.  But  taking  the  average  depth  as  4 
miles,  the  total  cubic  contents  of  the  sea  have  been  esti- 
mated at  584  millions  of  cubic  miles,  and  its  mass  or 
weight  at  2,494,500  billions  of  tons,  or  one  2346th  part 
of  the  total  mass  of  the  globe  (5,852  trillions  of  tons). 
On  the  one  hand  it  is  receiving  a  never-ending  flow  of 
waters  from  the  land,  and  on  the  other,  the  solar  rays 
are  constantly  elaborating  its  particles  into  vapour ;  but 
these  two  processes  of  waste  and  renewal  so  nicely 
balance  each  other  as  to  create  no  increase  or  diminution 
of  its  volume.  It  remains,  over  its  wide  expanses,  every- 
where at  the  same  level;  and  hence  the  level  of  the  sea 
at  mean  tide  is  assiuned  as  the  standard  for  the  measure- 
ment of  heights. 

r-  It  has  been  roughly  calculated,  that  if  the  present 
volume  of  the  ocean  waters  were  increased  by  ^,  the 
earth  would  be  covered  except  the  highest  mountains ; 
were  it  diminished  by  J,  the  largest  rivers  would  dwindle 
to  brooks,  the  principal  branches  of  the  ocean  would  be 
dried  up,  and  the  face  of  the  dry  land,  deprived  of  its  due 
proportion  of  moisture,  would  be  left  parched  and  deso- 
late. 

23.  Pressure. — The  pressure  of  the  waters  increasing 
with  the  depth,  it  was  till  lately  supposed  that  at  great 
depths  no  animal  and  vegetable  life  could  exist,  and  that 
therefore  the  abysses  of  the  great  deep  were  as  tenautlesa 


PHYSICAL   GEOGRAPHY. 


55 


66  PHYSICAL  GEOGRAPHY. 

and  barren  as  tlio  liighest  snow-clad  summits  of  the  land ; 
but  recent  explorations  have  discovered  the  existence  of 
numerous  forms  of  animal  life  at  the  greatest  depths. 
The  floor  qf  the  ocean  is  covered  in  most  places  with  ooze 
or  soft  mud;  but  in  great  depths,  over  thousands  of  square 
miles,  with  immense  deposits  of  microscopic  marine 
shells. 

At  the  depth  of  1000  feet,  water  is  compressed  -^-J-g-  of 
its  bulk;  at  one  mile  of  depth,  the  pressure  is  160  times 
that  of  the  atmosphere,  or  nearly  2400  lbs.  per  square 
inch ;  and  so  on  in  proportion. 

24.  Temperature. — Water  being  a  slow  conductor  of 
heat,  preserves  a  more  equable  temperature  than  the  at- 
mosphere, being,  therefore,  neither  so  warm  in  summer 
nor  so  cold  in  winter  as  the  adjacent  lands.  It  varies 
in  surface  temperature  according  to  latitude, — from  about 
80°  at  and  near  the  equator  to  30^  towards  either  Pole; 
but  below  100  fathoms  it  is  unaffected  by  solar  heat  or 
currents,  and  the  temperature  rapidly  declines.  Every- 
where, at  great  depths,  a  uniform  temperature  of  35°  has 
been  found — at  a  depth  of  7200  feet  at  the  equator,  and 
at  4500  feet  in  the  highest  latitudes.  The  mean  tempera- 
ture of  the  North  Atlantic  is  about  71J°,  and  that  of  the 
South  Atlantic  is  nearly  5°  less;  the  North  Pacific  is 
nearly  70°,  and  the  South  pacific  2J°  less,  while  the 
Indian  Ocean  is  warmer  than  the  Pacific.  This  equability 
of  temperature  acts  as  a  corrective  to  the  extremes  of 
climate  on  the  land  :  a  milder  air  from  the  sea  serves  to 
soften  the  severities  of  high  latitudes,  while  a  cooling 
breath  refreshes  the  drooping  animal  and  vegetable  life  of 
tropical  climes. 

25.  Saltness. — No  quality  of  the  ocean  is  more  con- 
spicuous than  its  saltness.  Were  all  the  salts  of  the  sea 
precipitated,  and  spread  out  equally  over  the  land,  they 
would,  it  has  been  computed,  cover  the  ground  one  mile 
deep  over  an  area  of  7,000,000  square  miles,  or  nearly 
tmce  the  area  of  Europe.  This  quality  is  owing  to  the 
presence  of  various  ingredients  held  in  chemical  solution 


COLOUR.  57 

in  its  waters — cliiefly  common  salt,  sulpliate  of  socla, 
chloride  of  lime,  and  magnesia.  It  amounts  to  about  3^ 
per  cent.,  or  nearly  half  an  ounce  to  the  pound.  This 
saltness  is  not  quite  uniform  in  all  parts  of  the  ocean. 
The  waters  of  the  Southern  Ocean  are  slightly  Salter  than 
those  of  the  Northern ;  and  the  gi'catest  saltness  occui-s 
along  the  parallels  of  20°  north  and  17^  south, — that  is, 
in  the  region  of  the  Trade  Winds,  which  cany  off  an 
excess  of  fresh  vapour  to  the  Equator.  Inland  seas,  from 
the  influx  of  rivers  and  less  evaporation,  are  in  general 
fresher  than  the  ocean  :  the  Baltic  is  only  half  as  salt ; 
while  the  Red  Sea,  in  a  rainless  and  riverless  region,  has 
an  excess  of  saltness.  Sea-water  is  heavier  than  fresh 
water,  which,  therefore,  floats  on  the  surface.  Hence  the 
waters  of  the  Amazon  are  perceived  more  than  200  miles 
out  in  the  ocean,  and  fresh  water  has  been  skimmed  from 
the  surface  of  the  sea.  It  also  freezes  less  readily,  not 
being  converted  into  ice  till  the  thermometer  falls  to  28  J* 
Fahr.,  w^hile  fresh  water  freezes  at  32^ — thus  keeping  a 
larger  surface  open  and  serviceable  to  man.  It  is  also 
less  vaporizable,  thus  limiting  the  amount  of  moisture 
given  ofi"  from  its  immense  expanse  to  the  comparati^'ely 
small  area  of  the  land. 

Tliis  salt,  which  subseiwes  these  and  other  important 
uses  in  the  economy  of  nature,  is  chiefly  derived  from 
ingredients  washed  down  by  rivers  from  the  soil.  For 
the  same  reason,  lakes  that  have  no  outlet  are  salt,  and 
from  constant  supplies  are  becoming  Salter,  as  the  ocean 
would,  were  its  salts  not  taken  up  and  secreted  by  the 
numberless  shell-fish  and  infusoria  of  its  waters. 

26.  Colour. — In  small  quantities  sea-water  is  colour- 
less ;  but  in  large  masses  it  is  of  various  shades.  In  the 
open  ocean,  shallow  waters  are  green,  while  those  of  gi-eat 
depth  are  indigo  blue.  These  colours  are  also  due  to  the 
comparative  freshness  or  saltness  of  the  water  :  the 
fresher  Northern  Seas  being  light  green,  while  the  Indian 
Ocean  in  the  Trade  Wind  region  is  dark  blue.  Other 
colom-s,   pecidiiir    to   particular    seas,  and   often  giving 


58  tUYSICAL  GEOGRAPHY. 

names  to  them,  as  Ked,  Black,  White,  Yellow,  Green, 
and  Vermilion,*  are  due  to  local  causes,  such  as  tho 
colour  of  the  bottom,  the  presence  of  river  water  in  large 
quantities,  and  countless  myriads  of  animal  and  vegetable 
organisms. 

MOVEMENTS  OF  THE  OCEAN:  AVAVES,  TIDES, 

CUREENTS. 

27.  Waves. — ^Waves  are  undulations  of  the  water 
without  progressive  motion.  They  are  produced  by 
winds,  and  are  not  sensibly  felt  to  any  great  dej)th.  They 
are  of  various  magnitude,  dependent  on  the  force  of  the 
wind,  from  a  gentle  ripple  to  billows  40  feet  in  height. 
The  greatest  waves  known  are  those  off  the  Cape  of  Good 
Hope  (formerly  called  the  "  Cape  of  Storms")  in  a  north- 
west gale,  when  they  measure  40  feet  from  trough  to 
crest ;  off  Cape  Horn  32  feet ;  in  the  North  Atlantic  20 
to  25  feet;  and  in  the  British  Seas  8  to  10  feet.  The 
Polar  Seas,  owing  to  their  great  floating  fields  of  ice,  are 
never  agitated  by  storms.  The  velocity  and  force  of  waves 
depend  primarily  upon  the  violence  and  continuity  of  the 
wind,  but  also  largely  upon  their  magnitude  and  the 
depth  of  water  which  they  traverse.  The  velocity  has 
been  calculated  of  a  wave  100  feet  broad,  over  water  100 
feet  deep,  at  15  miles  an  hour;  with  ten  times  these 
proportions  at  48  miles  an  hour;  and  with  100  times 
these  proportions  at  154  miles.  Their  pressure  is  some- 
times enormous,  having  been  estimated  as  high  as  6000 
lbs.  per  square  foot. 

28.  Tides. — The  tides  are  a  periodic  rising  and  falling 
of  the  waters  of  the  ocean,  caused  by  the  attraction  of 
the  sun  and  moon,  but  chiefly  of  the  latter,  on  account 
of  its  greater  proximity.  The  whole  body  of  the  earth  is 
influenced,  but,  from  their  mobility,  only  the  waters  of 

'  *  The  Green  Sea  (or  Sargasso  Sea)  lies  west  of  the  Azores  and 
Canary  Islands,  and  the  Vermilion  Sea  is  a  name  applied  to  tlie 
Gulf  of  California. 


TIDES. 


50 


the  globe  arc  sensibly  affectccl.  As  tlie  earth  rotates  on 
its  axis,  meridian  after  meridian  is  presented  in  succes- 
sion to  the  attractive  influence,  so  that  the  rising  waters 
are  drawn  along  in  a  great  tidal  wave  or  flow  around  the 
globe.  When  the  sun  and  moon  are  in  conjimction,  that 
is,  at  full  moon,  the  united  attractions  cause  the  highest 
or  spring  tides  ;  but  when  the  moon  is  in  her  quadratures, 
that  is,  in  her  first  and  last  quarters,  the  sun's  attraction 
acts  at  right  angles  to  that  of  the  moon,  and  produces  tho 
lowest  or  neap-tides.  The  moon's  attractive  power,  com- 
pared with  the  sun's,  is  as  100  to  38,  and  the  differenco 
between  Spring-tide  and  ISTeap-tide  is  as  7  to  3 


THE  SUN   AND   MOON   IN  COKJUNCTION,   PKODUCINQ  SPRING-TIDEii 


THE   SUN   AND   MOON    IN   OPPOSITION,    CALHIXG   NEAP  TlX>i;S. 

The  waters  most  directly  under  the  moon  bein^^  nearest 
are  most  attracted,  and  rise  highest ;  at  the  same  time, 
the  body  of  the  earth  also  is  drawn  towards  that  luminary 
so  as  to  leave  the  mobile  waters  on  the  opposite  side  of 
the  earth  behind;  hence  causing  them  to  bulge  out  to  an 


60  PHYSICAL   GfiOGRAPHY. 

equal  extent  witli  those  on  the  other  side.  There  are 
thus  two  high-waters  at  the  same  time  on  opposite  sides 
of  the  globe, — the  one  above,  the  other  beneath  the  hori- 
zon ;  while  the  other  two  sides,  having  their  waters 
drawn  aAvay  from  them,  have  low-water.  Every  place, 
therefore,  owing  to  the  earth's  rotation,  Avould  have  two 
high- waters  and  two  low- waters  every  24  hours ;  but  as, 
owing  to  the  moon's  revolution  round  the  earth  in  a 
month,  it  requires  24  hours  54  minutes  to  bring  the  same 
meridian  again  beneath  the  moon,  every  successive  tide  is 
from  20  to  27  minutes  later  than  the  preceding,  and  the 
alternate  tides  about  50  minutes.  The  waters  do  not, 
however,  immediately  obey  the  moon,  but  from  the  force 
of  inertia  require  an  interval  of  three  hours,  at  any 
given  meridian,  between  the  passage  of  the  moon  and 
high-water. 

29.  Tide-Waves. — Tides  are  highest  where  the  earth's 
surface  is  nearest  the  moon,  that  is,  between  the  tropics ; 
and  they  gradually  diminish  towards  the  poles.  Had 
our  planet  been  one  great  globe  of  water,  the  tides  would 
have  been  perfectly  regular  and  continuous  from  east  to 
west ;  but  from  the  masses  of  land  and  their  configura- 
tion, the  course  of  the  tidal  wave  is  much  obstructed  and 
deflected.  The  Southern  Ocean,  an  uninterrupted  ex- 
panse surrounding  the  globe,  may  be  regarded  as  the  area 
whence  arises  the  great  tidal  wave.  It  then  presses 
forwards  into  the  Pacific,  Indian,  and  Atlantic  Oceans, 
variously  modified  in  its  j)assage  by  the  obstructions  it 
meets  with.  In  the  Indian  and  Atlantic  Oceans,  owing 
to  their  configuration,  it  assumes  a  northerly  course. 

The  high-water  which  passes  Tasmania  at  (say)  mid- 
night reaches  Ceylon  in  twelve  hours,  and  Cape  of  Good 
Hope  in  about  thirteen  ;  it  is  off  Ne^^^oundland  in  other 
twelve  ;  in  twelve  more  it  has  rounded  the  north  of  Scot- 
land and  reached  Aberdeen  ;  in  other  twelve  it  is  at  the 
mouth  of  the  Thames  :  and  it  is  onlv  on  the  morninsf  of 
the  thiixl  day  that  it  has  brought  high- water  to  London 
Bridge. 


^ 


0 

r-> 


CURRENTS.  61 

Tlie  velocity  of  the  tide-wave  is  greatest  where  the 
ocean  is  freest  and  deepest.  In  the  Southern  Ocean  it 
travels  at  1000  miles  an  hour,  in  the  North  Sea  at 
not  more  than  50.  Its  height,  in  broad  open  exi>anse3, 
as  in  the  Pacific,  is  only  one  or  two  feet,  in  the  Southern 
Ocean  five  or  six,  in  the  Atlantic  and  Indian  Oceans  eight 
or  ten ;  but  in  inlets  of  the  sea,  with  broad  mouth? 
open  to  its  advance  and  narrowing  in  the  interior,  such 
as  the  Bay  of  Bengal,  Bay  of  Fundy,  Bristol  Channel, 
and  Solway  Firth,  it  may  rise  to  30,  40,  or  even  70  feet. 
In  river  estuaries,  the  tide  entering  and  converging  forms 
a  head  of  water  called  a  Bore,  from  10  to  30  feet  high  in 
diiferent  rivers,  and  of  great  velocity  and  destructiveness. 
Such  occur  in  the  Hooghly,  the  Amazon,  the  Garonne, 
and  the  Severn.  Inland  seas  and  gulfs,  as  the  Mediter- 
i-anean  and  the  Baltic,  whose  openings  are  narrow  and 
not  in  the  course  of  the  tidal  wave,  have  no  perceptible 
tides ;  and  tlieu*  areas  are  too  limited  to  generate  any 
tide-waves  of  their  own. 

The  South  Sea  Islands  appear  to  present  some  remark- 
able exceptions  to  the  ordinary  theory  of  the  tides  :  the 
heiorht  to  which  the  waters  rise  never  varies  more  than  a 
few  inches  ;  and  throughout  the  year  it  is  uniformly  low 
water  at  six  in  the  morning  and  six  in  the  evening,  and 
hit:rh  water  at  noon  and  midnifijht — a  fact  so  well  estab- 
lished  that  the  word  for  high-water  and  for  midnight  is 
the  same. 

30.  Currents. — The  ocean  currents  are  of  three  kinds  : 
— constant,  periodical,  and  variable.  The  constant  are 
due  primarily  to  the  unequal  temperatui'es  and  densiticp, 
of  the  waters,  and  secondarily  to  the  rotation  of  the 
eai-thand  the  Trade-Winds;  the  periodical,  most  ccramon 
in  the  Indian  Ocean,  are  caused  by  the  tides,  the  mon- 
soons, and  land  and  sea  breezes  within  the  tropics ;  and 
the  variable  are  produced  by  local  peculiarities  of  tides, 
winds,  configuration  of  the  land  and  sea-bottom,  the 
melting  of  polar  ice,  etc.  Drift-Currents  are  caused  by 
the  long-continued  action  of  the  wind  upon  the  waters  at 


62  PHYSICAL   GEOGRAPHY. 

or   near   tlie   surface;    but    dcep-sea    currents   extend 
hundreds  of  fathoms  do^^'^l. 

31.  Causes  of  Currents. — Currents  are  necessary  to 
maintain  the  equilibrium  of  the  ocean.  The  waters  of 
the  equatorial  regions  being  greatly  heated,  lose  their 
specific  gravity  and  rise  to  the  surface,  a  prodigious 
quantity  at  the  same  time  passing  off  by  evaporation — a 
foot  deep  of  water  being  evaporated  in  a  few  days.  The 
waters  from  the  Poles  being  colder,  and  therefore  heavier, 
set  in  as  an  under  current  to  supjDly  their  place.  On  the 
other  hand,  the  waters  of  the  polar  regions,  being  con- 
densed by  cold,  subside,  and  the  warmer  and  therefore 
lighter  waters  from  the  Equator  make  for  the  Poles  to 
restore  the  equilibrium  in  those  regions.  Thus  two 
primary  sets  of  currents  are  established — two  light,  warm, 
surface  currents  noi-th  and  south  from  the  Equator  to 
the  Poles,  and  two  heavy,  cold,  under  currents  from  the 
Poles  to  the  Equator.  But  the  latter,  advancing  by 
degrees  towards  the  Equator,  where  the  earth's  rotation 
is  most  rapid  (viz.,  1000  miles  per  hour),  cannot  all  at 
once  acquire  the  increasing  velocity,  but  fall  behind  the 
rest  of  the  equatorial  surface,  flowing  westwards,  and 
forming  the  Great  Equatorial  Currents.  By  an  oppo- 
site course  of  reasoning,  it  may  be  shown  that  currents 
from  the  Equator  must  have  a  tendency  eastwards. 
Hence  arises  the  great  circulatory  system  of  the  ocean. 
By  the  interruptions  and  modifications  of  land,  sea- 
bottom,  and  other  local  causes,  this  great  flow  is  broken 
up  into  various  minor  currents  of  different  directions, 
volumes,  velocities,  and  temperatures. 

The  General  Law  of  the  Directions  of  Ocean  Currents 
may  be  thus  stated  : — 

(1)  Within  the  Tropics  they  flow  westwards. 

(2)  In  the  Temj^erate  Zones,  eastwards. 

(3)  In  high  latitudes,  from  the  Poles  to  the  Equator. 

32.  Equatorial  Currents. — These  may  be  considered  as 
general  movements  of  the  waters  of  the  globe  from  east 
to  west,  in  opposition  to  the  diurnal  motion  of  the  earth. 


THE    GULF   STREAM.  C 


•> 


In  tlieir  origin  tliey  are  all  more  or  less  dependent  upon 
drift  currents  from  the  Antarctic  Ocean. 

(1)  An  Antarctic  Drift  Current  to  the  north-east 
strikes  against  the  shores  of  South  America,  and  flows 
northwards  till  it  reaches  Peru,  when  it  turns  west- 
vrards  as  jxirt  of  the  great  Equatorial  Current  of  the 
Pacific.  In  a  belt  3500  miles  wide,  that  is,  the  entii-e 
Torrid  Zone,  the  latter  sweeps  boldly  across  to  tlie  Indian 
Archipelago  and  South-Eastern  Asia.  The  Japan  Cur- 
rent, known  to  the  Japanese  as  the  Kuro-Siwo,  or  Black 
Stream,  is  here  set  off  to  the  north-east,  bearing  its  warm 
waters  into  the  North  Pacific,  and  the  New  South  Wales 
and  New  Zealand  Currents  to  the  south,  while  a  consider- 
able portion  returns  to  the  east  as  a  counter-current. 

(2)  The  Equatorial  Current  of  the  Indian  Ocean 
makes  its  way  across  to  Africa,  by  which  it  is  deflected 
to  the  south.  From  the  obstruction  of  the  Agulhas  Bank, 
off  the  Cape  of  Good  Hope,  the  main  poi-tion  is  turned 
back,  and  helps  to  form  the  Counter  Current  of  the 
Indian  Ocean,  which,  with  a  speed  of  50  miles  a-day,  and 
along  the  direct  route  from  the  Cape  to  Australia,  is  of 
important  service  to  navigation. 

(3)  The  South  African  Current,  proceeding  north- 
wards, joins  the  Equatorial  Current  of  the  Atlantic, 
which,  at  300  or  400  miles  ofl'  Cape  St.  Roque,  divides 
into  two  main  branches — the  Brazil  Current,  south- 
west along  the  South  American  coast,  and  the  Guiana 
Current,  north-west  into  the  Caribbean  Sea  and  Gulf  of 
Mexico. 

33.  The  Gulf  Stream. — The  most  remarkable  of  all  the 
oceanic  currents  is  the  Gulf  Stream,  so  called  from  its 
origin  in  the  Gulf  of  Mexico.  Formed  by  the  accumu- 
lated waters  of  the  E(iuatorial  Current  in  the  confined 
basin  of  this  gulf,  it  rushes  out  through  the  narrow 
Channel  of  Florida,  and  flows  north-east  almost  parallel 
to  the  coast  of  North  America,  till  it  reaches  the  Gre^at 
Bank  of  ]S^e^\^oundland.  Thence  it  spreads  out  across 
the  Atlantic,  part  of  its  waters  turning  southwards  by  tho 


64  PHYSICAL   GEOGRArilY. 

Azores,  again  to  join  the  Equatorial  Current;*  but  the 
greater  part  proceeding  north-east,  bathes  the  British  Isles 
and  the  shores  of  Norway,  and  ultimately  loses  itself  in 
the  Arctic  Ocean.  This  great  "  river  in  the  ocean,"  from 
the  Gulf  of  Mexico  to  the  Azores,  is  3000  miles  in  length, 
and  its  greatest  breadth  120.  At  first  its  speed  is  4  miles 
an  hour;  but  this  gi-adually  declines  as  it  becomes  more 
diffused.  In  the  Strait  of  Florida  its  temperature  is  86°, 
or  9°  above  the  surrounding  waters;  and  off  Newfound- 
land, in  winter,  it  is  25°  to  30°  warmer  than  the  neigh- 
bouring seas,  thus  causing  the  dense  fogs  of  that  region. 
It  is  a  great  dispenser  of  heat  and  moisture  in  its  course. 
To  its  influence  is  owing  the  verdure  of  the  "  Emerald 
Isle,"  and  the  mildness  of  the  climate  of  Western  Europe 
compared  with  countries  elsewhere  of  corresponding  lati- 
tudes. It  arrests  the  chilling  Arctic  icebergs,  which  melt 
away  in  its  tepid  waters.  It  is  of  a  deep  indigo  blue  as 
long  as  its  current  is  deep  and  narrow;  and  the  line  ot 
demarcation  between  it  and  the  adjacent  waters  is  so 
marked,  that  a  vessel  may  be  seen  floating  one  half  in 
the  Gulf  Stream,  and  the  other  in  the  common  water  of 
the  sea;  and  two  buckets  let  down,  one  at  the  bow,  the 
other  at  the  stern,  will  draw  up  water  differing  in  tem- 
perature by  no  less  than  30*^. 

34.  The  Arctic  Current. — Just  as  a  cold  Antarctic  cur- 
rent flows  into  the  Pacific,  a  cold  Arctic  current  flows  into 
the  Atlantic.  A  united  stream  from  the  east  and  west 
sides  of  Greenland  presses  strongly  south  till  it  meets  the 
Gulf  Stream  off  Newfoundland,  sending  its  icebergs  far 
into  the  Atlantic.  Here  it  divides — one  portion  flowing 
south  as  an  under  current  to  the  Caribbean  Sea,  and  the 
other  south-west  along  the  shores  of  the  United  States. 
Whilst  the  Gulf  Stream  warms  the  coasts  of  Europe,  the 
Arctic  Current  cools  those  of  America,  producing  a 
marked  climatic  contrast  between  the  opposite  shores  of 

*  It  was  the  wreck  cast  ashore  on  the  Azores  by  this  current 
that  suggested  to  Columbus  the  idea  of  land  to  the  west,  which 
led  to  the  discovery  of  America. 


USES    OF    CURRENTS. 


(35 


the  Atlantic ;  but  it  atTords  an  excellent  supply  of  lish 
denied  to  warmer  seas.  "  It  replaces  the  warm  water 
sent  tlu'ough  the  Gulf  Stream,  and  modifies  the  climate 
of  Central  America  and  the  Gulf  of  ^Mexico,  which,  but  for 
this  beautiful  and  benign  system  of  aqueous  circulation, 
would  be  one  of  the  hottest  and  most  pestilential  in  tho 
world." 

35.  Uses  of  Currents. — These  great  ever-flowing  ocean 
streams  preserve  the  equilibrium  of  the  sea  by  the  con- 
stant interchange  of  waters,  and  thus  maintain  the  almost 
uniform  saltness,  and  therefore  the  purity  and  salubrity 
of  the  ocean;  they  soften  the  extremes  of  climate  in 
different  regions  of  the  earth,  by  imparting  to  them  the 
temperature  of  theii-  own  waters;  and  by  facilitating  the 
course  of  the  navigator,  who  learns  to  take  advantage 
of  them,  they  promote  the  progi-ess  of  commerce  and 
civilization. 


Principal  Ocean  Currents. 


PACIFIC  OCEAN. 


Antarctic    Drift    Car 

rent, 

Cape  Horn  Current, 
Peruvian,     Chili,     or 

Humboldt's  Current, 
Equatorial  Cuxrcat,  . 


Direc-  ' 
tioa.* 

flowing 

N.E. 
E. 

1 1 

W. 

Japan    Current,    or 
Kuro-Siwo,       .        .  flowing 

New  South  Wales  Cur- 
rent  ,, 

Mexican  Current : 
in  winter  half-year.       ,, 
in  summer  half-year.    „ 


INDIAN  OCEAN. 


Equatorial  Current,    .  flowing  ,    W. 
Mozambique  Current,      ,,       |     S. 


Equatorial  Current, 
Brazil  Current,    . 
Guiana  Current, . 
Gulf  Stream, 


.  fluwing 


Agulhas  or  Cape  Cur- 
rent,        .        .       .  flowing 
Counter  Current,       .     „ 


ATLANTIC  OCEAN. 

North  African  and 
Guinea  Current,      .  flowing 

Arctic   or   Greenland 
Current,  .       .       .     „ 


W. 

s.w. 

N.W. 
N.E. 


"Direc- 
tion. 


3. 


N.E 

S.    ( 

S.E. 
N.W. 


W. 
E. 


*  Currents  are  named  after  the  direction  to  which  they  flow; 
thus,  an  easterly  current  is  one  flowing  towards  the  east ;  -winds, 
on  the  other  hand,  are  named  after  the  direction  from  which 
they  blow. 

23  E  E 


CG  PHYSICAL   GEOGRArny. 


EXERCISES, 

1.  What  are  tlie  relative  proportions  of  the  areas  of  the  oceans  to 
each  other?  Draw  out  a  comparative  view  of  these  areas  simihir 
to  that  of  the  continents  on  page  18,  and  on  the  same  scale. 
Compare  them  with  that  of  the  British  Islands.  Why  is  the 
area  of  the  Antarctic  Ocean  not  stated  in  the  Table,  page  50  ? 
Where  is  the  Atlantic  broadest?  where  narrowest?  Name  the 
peninsulas  and  island  chains  that  shut  in  the  seas  on  the  east  of 
Asia.  Name  the  projections  that  look  across  to  indentations  on 
tlie  opposite  shores  of  the  Atlantic.  Which  countries  on  the 
Atlantic  are  most  worn  by  its  waters  into  fiords,  firths,  or  lochs? 
Name  similar  inlets  on  the  shores  of  the  Pacific.  What  islands 
or  peninsulas  shut  in  the  North  Sea?  the  Caribbean?  the  Gulf  of 
St.  Lawrence  ?  the  INIediterranean  ?  the  Baltic  ?  Gulf  of  Mexico  ? 
and  Hudson's  Bay?  Write  out  a  descriptive  account  of  the  Dis- 
tribution of  Water.     Draw  a  map  of  the  two  Hemispheres, 

2.  Name  the  seas  or  oceans  which  you  would  expect  tobe  shallow, 
and  those  you  would  expect  to  be  deep, — and  state  why.  Com- 
pare the  greatest  and  the  mean  height  of  the  land  of  the  globe 
Math  the  greatest  and  the  mean  depth  of  the  ocean.  Point  out 
the  seas  named  after  colours,  and  account,  if  you  can,  for  the 
name  of  each.  Name  and  point  out  as  many  rivers  as  you  can 
named  after  the  colour  of  their  waters,  and  account,  if  you  can, 
for  the  difi'erent  colours. 

3.  Could  you  illustrate  by  a  simple  experiment  the  reason  why 
the  Polar  seas  are  comparatively  so  calm  ?  In  what  respect  do 
waves,  tides,  and  currents  difi'er  essentially  from  each  other  ? 
Write  out  in  your  own  words  a  descriptive  account  of  tides. 
"VVliich  are  cold  currents  ?  and  which  are  warm  ?  Which  cur- 
rents branch  off  from  the  Equatorial  currents  ?  and  which  join 
them?  Which  currents  meet  each  other?  _  Which  should  be 
most  serviceable  to  a  vessel  bound  from  Britain  to  Australia? 
and  which  on  her  return  voyage  ?  What  portion  of  the  ocean  is 
surrounded  by  the  Gulf  Stream  ?  Which  current  of  the  Pacific 
corresponds  to  the  Gulf  Stream  in  the  Atlantic  ?^  Write  out  in 
your  own  words  a  descriptive  account  of  the  Gulf  Stream.  Draw 
a  map  of  the  Ocean  Currents. 


TRANSTIIATIC    SPRINGS.  C7 

CHAPTER  IV. 
WATERS  OF  THE  LAND. 

Springs  —  Pavers  —  Characteristics  of  Rivers  —  Classification  of 
Rivers — River-Sources — River-Basins — Velocity  of  Rivers — 
"Waterfalls  —  River-Mouths  —  Floods  of  Rivers  —  Table  of 
River-Systems — Lakes— Characteristics  of  Lakes  —  Classi- 
fication of  Lakes — Distribution  of  Lakes — Table  of  Principal 
LakcSf 

SPRINGS. 

36.  Of  the  rain  wliich  falls  upon  the  siirf\ice  of  the 
earth,  one  large  portion  runs  off  in  streams  back  to  the 
ocean,  from  which  it  originally  came,  another  is  evaporated 
into  the  atmosphere,  ■svhile  a  third  soaks  into  the  soil,  and 
seeks  a  way  to  a  gi'eater  or  less  distance  into  the  boAvels 
of  the  earth,  but  afterwards  reappears  at  the  surface  in 
what  are  called  Springs.  These  springs  are  of  three 
kinds,  viz.,  Land  Springs,  Transtratic  Springs,  and 
Deep-seated  Springs. 

(1)  Land  Springs  are  derived  from  the  waters  which 
have  accumulated  near  the  surface,  having  soaked  down 
through  a  pervious  layer,  such  as  sand  or  gravel,  been 
intercepted  by  an  impervious  one  like  clay,  and  collected 
in  its  iiTegularities  or  hollows.  Such  springs  yield  the 
supply  to  many  of  our  wells,  but  they  are  liable  to  fail  in 
a  dry  season,  and  to  be  tainted  v.ith  impurities  from  the 
surface. 

(2)  Transtratic  Springs,  as  they  have  been  recently 
called,  are  those  that  yield  their  waters  at  a  considerable 
distance  from  their  place  of  reception,  having  been  con- 
veyed tliither  through  a  stratum  of  a  porous  character 
lying  between  two  which  arc  impervious.  The  water  has 
been  received  as  rain  at  the  surface  A  (sec  annexed  fig.) 
lying  between  two  impervious  rocks,  B  and  C;  it  makes 
its  way  through  the  sti-atum  till  it  reappears  at  A'  in  the 
form  of  a  spring.     Such  often  well  forth  b}'-  the  margin 


68 


PHYSICAL    GEOGRAPHY. 


of  a  river,  at  tlie  bottom  of  a  valley,  or  on  the  green  soft 
turf  on  the  mountain  side.  If  an  opening  is  sunk  from 
B  to  the  water-bearing  rock  A  A',  the  water  will  rise  to 
the  level  of  its  source.  Such  is  the  principle  of  Artesian 
wells,  by  which  water  is  raised  from  great  depths.  But 
the  water  often  finds  its  way  up  naturally  by  means  of 
faults  or  fractures  in  the  overlying  rock.  This  is  the 
most  numerous  and  coi:>ious  class  of  springs,  and  they 
are  frequently  uniform  in  temperature  and  regular  in 
quantity. 


(3)  Deep-seated  Springs  derive  theii*  waters  from  a 
great  depth  by  means  of  cracks  or  crevices  in  the  rocks. 
They  generally  contain  a  greater  or  less  quantity  of 
foreign  matter  derived  by  solution  from  the  rocks  through 
which  they  have  passed,  and  often  imparting  to  them 
valuable  medicinal  qualities.  The  quantity  of  solid  matter 
varies  from  -^V  of  an  ouiijce  to  16  ounces  per  gallon,  and 
the  general  name  by  which  they  are  known  is  mineral 
springs.  They  may  be  saline  or  salt,  as  at  E2:)som, 
chalybeate  or  ii'on,  as  at  Tunbridge  Wells,  sulphurous,  as  at 
Harrowgate,  silicious  or  flinty,  as  the  Geysers  of  Iceland, 
calcareous  or  limy,  as  in  Italy,  and  carbonated  or  abound- 
ing with  carbonic  acid,  as  at  Auvergne  in  France.  If 
the  water  is  warm,  the  sj^rings  are  termed  thermal,  show- 
ing they  have  sprung  from  a  great  depth,  where  the  tem- 
perature is  so  much  greater  than  at  the  surface.  Most 
thermal  springs  are  below  100°^.;  but  they  may  equal  oi 


OCEANIC  niVF.Ttg.  CO 

even  exceed  the  temperature  of  boiling  water  (2 12'),  as 
in  the  Geysers.  Indeed,  these  springs  are  found  most 
plentifully  in  regions  which  are,  or  have  been,  the  seats 
of  volcanic  agency, 

rjVERS. 

37.  Characteristics  of  Rivers. — Rivers  are  the  great 
agencies  of  nature  for  carrying  the  superfluous  moisture 
otf  the  face  of  the  land.  It  has  been  estimated  that  only 
about  Ys  of  the  aqueous  deposits  of  the  atmosphere  finds 
its  way  back  directly  to  the  ocean,  its  original  repository 
— the  rest  being  applied  to  the  support  of  animal  and 
vegetable  life,  or  carrieil  off  by  evaporation.  R-ivers 
irrigate  as  well  as  drain  the  soil,  and  carry  ofl"  impurities 
and  debris  to  the  ocean.  They  are,  besides,  important 
agents  in  the  commercial  and  social  economy  of  nations, 
forming  ready  and  effective  means  of  intercourse.  But 
for  great  rivers  the  interior  of  the  continents  would  have 
been  impassable  wilds,  shut  out  from  civilization.  The 
banks  of  rivers  are  the  sites  of  most  of  the  great  cities  of 
the  world;  and  the  seats  of  commercial  and  manufactur- 
ing industry  are  almost  invariably  grouped  along  their 
course. 

38.  Classification  of  Rivers. — Rivers  are  either  Oceanic 
or  Continental. 

(1)  Oceanic  rivers  are  those  which  flow  into  the  ocean 
directly  or  indirectly.  About  440  considerable  rivers  of 
this  class  are  found  in  the  Old  World,  and  about  140  in 
the  New ;  but  manv  of  those  in  the  New  World  are  of 
greater  length  and  volume.  From  the  vertical  configura- 
tion of  the  globe,  already  explained,  the  chief  slopes  in 
both  worlds  are  towards  the  Arctic  and  Atlantic  basins, 
while  the  Pacific,  though  the  largest  ocean,  receives  but 
few  rivers.  With  two  or  three  exceptions,  all  the  large 
rivers  of  the  world  are  in  the  Northern  Hemisphere;  the 
Amazon  belongs  to  both  sides  of  the  Equator.  The  most 
important  rivers  of  the  globe  have  an  easterly  course, 
while  those  with  a  westerly  course  are  unimpoi-tant. 


70  niYSICAL  GEOGRAPHY. 

(2)  Continental  rivers  are  tliose  wliich  do  not  rcacli  tlio 
ocean,  but  are  confined  to  the  continent,  discharging  their 
waters  into  inland  lakes  with  no  outlet,  or  losing  them- 
selves, through  evaporation,  in  sands  or  marshes.  In  the 
Old  World  is  an  extensive  Basin  of  Continental  Streams, 
extending  from  near  the  Baltic  and  Black  Seas  through 
the  whole  of  Inner  Asia  eastwards  to  near  the  Yellow 
Sea.  It  comprises  the  Volga,  the  largest  river  of  Europe, 
the  depressed  regions  around  the  Caspian  Sea  and  Sea 
of  Aral,  and  the  great  table-land  of  Central  Asia,  and  is 
3,000,000  square  miles  in  area.  Similar  regions,  but  of 
limited  extent,  are  the  Basins  of  the  Dead  Sea,  Utah, 
the  Mexican  Table-land,  and  the  Plateau  of  Bolivia, 
a  district  in  Morocco  south  of  the  Atlas  range,  and, 
perhaps,  also  the  Basin  of  Lake  Tchad  in  Central 
Africa. 

39.  River-systems. — Bivers  are  commonly  gi'ouped  into 
river-systems,  according  to  the  oceanic  or  continental 
basin  into  which  they  descend,  whether  directly  or  indi- 
rectly. The  widest  generalization  of  this  kind,  therefore, 
will  be  into  four  great  oceanic  systems,  and  into  the 
several  minor  continental  ones  which  belong  to  the  con- 
tinental basins  just  indicated.  For  the  different  river- 
systems  of  the  globe,  see  pages  76-9. 

A  binary  river-system  consists  of  two  rivers  which  rise 
near  each  other,  pursue  a  divergent  course,  though  in  the 
same  general  direction,  and  finally  join  or  fall  into  the 
same  sea,  such  as  the  Euphrates  and  Tigris. 

40.  River-sources. — Bivers  in  general  take  their  rise 
in  springs  or  lakes,  and  sometimes  from  the  melting  of 
snows  and  glaciers.  Some,  like  the  Ganges,  issue  at  once 
from  a  glacier  a  large  river ;  but  most  swell  by  degrees 
from  tmy  rills.  Most  large  rivers  have  their  head-waters 
in  high  lands,  but  the  water-shed  of  a  country  is  often  of 
no  great  elevation,  as,  for  example,  the  swamps  of  Bussia 
in  the  Great  Plain  of  Europe,  and  the  north  of  North 
America,  where  the  sources  of  rivers  flowing  in  opposite 
directions  are  so  low  as  to  be  united  in  times  of  flood,  or 


RIVER-BASINS. 


Tl 


pcrmnncntly  by  means  of  lakes.  The  head-waters  of  the 
Mississippi  are  thus  connected  with  the  southern  tribu- 
taries of  Lake  Winnipeg,  and  the  River  Illinois  with 
Lake  Michigan;  Lake  Athabasca  and  Lake  Wollaston  are 
connected  with  both  the  Arctic  Ocean  and  Hudson's  Bay. 
The  Orinoco  in  South  America  sends  off  a  branch,  the 
Casiquiare,  which,  after  a  course  of  180  miles,  joins  the 
Eio  Negi'O,  a  leading  tributary  of  the  Amazon.  The 
Zambesi  and  the  Congo  both  rise  in  Lake  Dilolo  in 
Centnil  Africa,  and  thus  unite  the  Indian  and  the  Atlan- 
tic Oceans. 

41.  River-basins.  —  A  river  and  its  tributaries,  or 
aflSuents,  are  distributed  like  the  stem  and  branches  of  a 
tree,  or  the  veins  and  arteries  of  the  body;  and  the  whole 
area  over  which  they  are  spread  is  tenned  the  river-basin. 


Labgest  PvIver-Basii^^s. 


Riveu-Basik, 


Arei  in 
Sq.  Miles. 


EUROrE. 

Volg.i, 

Danube,  

Don, 

Dnieper, 

Northern  Dwina, 

Neva, 

Rhine, 

Vistula, 

Elbe 

Oder, 

ASIA. 

Obi 

Yenisei 

Lena, 

Anioor, 

Yang-tse-kiang 

Ganges, 

Indus, 

Iloangho, 

Brahmaputra, ^ 

Sir-daria, 

Tigris  and  Euphrates, .. 
Tarim, 


520,000 

310,000 

205,000 

200,000 

144,000 

91,000 

87,000 

76,000 

57,000 

53,000 


1,250,000 
1,110,000 
960,000 
900,000 
76(^,000 
420,000 
400,000 
400,000 
350,000 
320,000 
230,000 
240,000 


River-Basi>', 


Area  in 
Sq.  Miles. 


AFRICA.* 

Nile I     620.000 

Zambesi, I     4o2,000 

AUSTRALIA. 
Murray, 1    250,000 


NORTH  AMERICA. 


Mississippi, 

Mackenzie  and  Athabasca, 
Saskatchewan  and  Nelson, 

St.  Lawrence, 

Columbia, 

Rio  Grande 

Rio  Colorado, 


1,244,000 

600,000 
490,000 
400,000 
263,000 
250,000 
230,000 


SOUTH  AMERICA. 


Amazon 

La  Plata  (Parana,  «tc.), 

Orinoco, 

San  Francisco, 


2,000,000 

1,200,000 

337,000 

250,000 


*  Tlie  interior  of  Africa  being  as  yet 
imperfectly  explored,  no  sufTicient 
estimate  of  the  extent  of  most  of  its 
river-basins  can  be  made. 


72  ^HYStCAti  GHoGtJAPHY. 

The  extent  of  basin  is  one  of  tlie  most  important  elements 
in  estimating  the  importance  of  a  river.  Of  the  larger 
rivers  the  largest  basins  are  in  America,  and  the  smallest 
in  Europe.  The  Amazon  has  the  largest  basin  and 
Volume,  and  the  Mississippi-Missouri  the  longest  course 
|4382  miles). 

The  Amazon  (4000  miles  in  length)  hcas  a  basin  of  2,000,000 
square  miles  (more  than  half  of  Europe),  with  60,000  miles  of 
navigation.  It  has  more  than  twenty  tributaries,  navigable 
almost  to  their  sources,  and  equal  in  size  to  the  largest  rivers  of 
Europe.  Near  its  mouth  it  is  180  miles  wide ;  tides  ascend  for 
400  miles  from  the  Atlantic ;  and  its  fresh-water  current  is  per- 
ceived 200  miles  out  at  sea. 

42.  The  velocity  of  a  river  depends  chiefly  upon  the  de- 
clivity of  its  basin,  the  form  of  the  channel,  and  the 
volume  of  water ;  but  the  average  rate  is  from  three  to 
four  miles  an  hour  in  the  lower  course.  But  the  fall  is 
greatest  in  the  uj)per  course,  where  the  stream  is  only  a 
mountain  torrent  and  unnavigable.  Winding  rivers  have 
the  slowest  current.  Were  it  not  for  the  friction  of  the 
banks  and  bottom,  the  accelerating  force  of  gravity  would 
increase  the  velocity  to  an  alarming  degree.  Thus,  the 
Thames,  falling  100  feet  in  250  miles,  would  run  with  a 
speed  of  54  miles  an  hour;  and  the  Khone,  falling  900 
feet  in  645  miles,  at  164  miles  an  hour.  Of  large  rivers, 
the  Yolga  has  the  least  fall — 633  feet  in  2400  miles;  the 
Ganges  the  greatest — 13,800  feet  in  1500  miles.  For 
400  miles  from  its  mouth  the  Amazon  falls  y^-  of  an  inch 
per  mile,  and  the  Plata  -^^  of  an  inch. 

43.  Waterfalls.— A  declivity  of  1  foot  in  200  renders  a 
river  unnavigable ;  a  greater  slope  forms  rapids;  and  a 
perpendicular  descent  a  cascade  or  cataract.  The  most 
celebrated  falls  are  those  of  Niagara  in  North  America ; 
but  they  are  far  surpassed  in  breadth  and  volume  of 
water  by  the  Victoria  Falls  on  the  Zambesi,  in  South 
Africa. 

The  Falls  of  Niagara  are  formed  by  the  Kiver  Niagara 
(a  section  of  the  Kiver  St.  Lawrence  so  called),  which 


VICTORIA   FALLS. 


73 


unites  Lakes  Erie  and  Ontario.  Tliey  consist  of  two 
cataracts,  separated  by  Goat  Island,  viz.,  the  Horse-slioe 
Fall,  on  the  Canadian  side,  1800  feet  wide,  and  154  in 
perpendicular  depth  ;  and  the  American  Falls,  600  feet 
in  breadth,  and  1G3  in  depth.  It  is  estimated  that 
the  falls  discharge  700,000  tons  of  water  per  minute ; 
their  noise  may  be  heard  miles  off,  and  the  clouds 
of  spray  thro^\'n  up  may  be  seen  at  a  distance  of  many 
miles. 


FALLS   OF   NIAGARA. 

The  Victoria  Falls  are  described  by  Dr  Livingstone, 
who  discovered  them,  as  the  most  wonderful  sight  he  had 
witnessed  in  Africa.  The  Zambesi,  1000  yards  wide, 
plunges  at  a  single  leap  into  a  chasm  100  feet  deep,  and 
extending  right  across  the  river-bed,  and  then  rushes 
away  at  right  angles  to  its  former  course  for  a  distance  of 
30  miles,  enclosed  between  deep  basaltic  rocks  not  more 
than  100  feet  apart.  The  native  name,  INIosioatunya 
(''smoke  sounds  there"),  refers  to  five  singular  columns 
of  dense  spray  that  rise  above  the  falls. 


u 


niYSicAL  GEOGiiAriiY. 


The  following  are  some  of  tlie  most  remarkable  water- 


falls : — 


Total  Height. 

2400  feet. 

1400 

1000 

940 

500 

80 

70 


if 


Oreo  Falls,  at  Monte  Eosa  (Alps),  .     -  .     -   .        . 

Gavarnie,  on  a  small  stream  in  tlie  Pyrenees, 

Staubtoach,  near  Lantcrbrunnen,  Switzerland, 

Maanelvan,  in  Norway,  ... 

Velino,  near  Terni,  in  Italy  (artificial),   . 

Tivoli,on  the  Teverone,  18  miles  N.E.  of  Eome  (artificial), 

Rheinfall,  on  the  Rhine  at  Schaffliaiisen,         .         . 

Falls  of  Clyde,  three  in  number,  Scotland,       .  highest  '  -^84: 

Victoria  Falls,  or  Mosioatunya,  on  the  Zambesi,     .  100 

Murchison  Falls,  on  the  Nile  (between  Victoria  and      '. 

Albert  N'yanza,) 120 

Montmorenci  Falls,  8  miles  from  Quebec  (GO  feet  broad),  250 
Niagara  Falls,  on  the  Pdver  Niagara,  .        154  and  163 

Missouri  (Great Tails),  five  in  number,       .         highest     75 
Falls  of  the  Madeira,  in  Brazil  (^-mile  broad),  19  in 

^       number, highest    100    „ 

■  *'  The  loftiest  waterfall  in  the  world  (unless  exaggerated)  is  to 
be  found  in  the  Yohamite  Valley,  in  Mariposa  County,  Cali- 
fornia, where  a  river,  as  large  as  the  Thames  at  Richmond, 
makes  a  single  leap  of  2100  perpendicular  feet,  the  total  height 
of  the  fall  being  3100  feet."  .    *  -        •  ♦•.. 

44.  River  Mouths. — ^When  the  coast  is  high  and  rocky, 
rivers  fall  into  the  sea  by  a  single  deep  channel  or  estu- 
ary, like  the  firths  of  Scotland  and  the  fiords  of  Norway. 


>> 


DELTA   OF  THE   NILE. 


When  the  coast  is  low,  the  soil  washed  do-wn  by  rivers 
which  traverse  alluvial  plains  is  deposited  near  their 
mouths  as  the  current  slackens,  and,  accumulating  for 


FLOODS  OP  iiivEns.  Tj 

a,^cs,  forms  deltas,  so  called  from  tlicir  rcscinLlancc  to  tlio 

Greek  letter  a   (called  Delta.)     The  river  finds  its  ■way 

through  the  deposited  alluvium  by  means  of  numerous 

channels.    The  deltas  of  the  Nile,  the  Ganges,  and  the 

Mississippi,  arc  the  most  famous. 

The  Delta  of  the  Ganges  is  300  miles  in  length,  and  22,000  sqnaro 
miles  in  area.  The  river,  ^  of  whose  volume  consists  of  earthy 
matter,  annually  deposits  sediment  equal  to  42  times  the  Great 
Pyramid  of  Egj-pt.  The  black  mud  with  which  the  Nile,  when 
in  Hood,  is  loaded,  and  which  is  spread  out  over  the  valley  to 
fertilize  it,  or  carried  out  to  sea,  amounts  in  one  year  to  140,000,000 
tons.  The  Hoang-ho,  or  Yellow  Ilivcr,  traversing  the  great 
alluvial  plain  of  China,  discharges  in  one  hour  2,000,000  cubic 
feet  of  earth.  ... 

45.  Floods  of  Rivers. — Pvivers  are  subject  to  inunda- 
tions either  occasional  or  periodical.  The  former  prevail 
in  temperate  latitudes,  and  are  caused  by  hea^vy  rain- 
falls, the  rapid  melting  of  snows  in  spring,  and  the  like. 
The  periodical  inundations  characterise  the  rivers  of 
tropical  regions,  and  are  either  annual  or  semi-annual. 
The  annual  inundations  are  due  to  the  heavy  tropical 
rains  of  certain  seasons  of  the  year.  In  rivers  north  of 
the  equator,  as  the  Nile,  the  Niger,  the  Ganges,  and  the 
Orinoco,  the  flood  is  at  its  heiglit  in  August ;  but  in  those 
south  of  the  equator,  as  the  Amazon,  the  height  is  attained 
in  March.  The  semi-annual  floods  are  due  at  the  one 
season  to  periodic  rains,  and  in  the  otlier  to  the  melting 
of  snows  in  the  mountain-region  of  their  head-waters. 
The  Tigris  and  the  Mississippi  are  thus  flooded.  These 
periodic  floods  occur  with  wonderful  regularity  both  in 
time  and  amount  of  overflow.  In  tropical  countries  many 
rivers  exist  only  in  the  rainy  season,  as  in  South  Africa 
and  Australia :  their  dry  beds  are  known  as  nullahs  in 
India,  wadies  in  Arabia,  and  creeks  in  Australia. 

In  tropical  countries,  rivers  which  rise  in  the  regions 
of  perpetual  snow  experience  a  daily  flood,  caused  by  the 
melting  of  snows  by  the  solar  rays ;  while  some  in  Peru 
and  Chili,  being  fed  entirely  in  this  ^vay,  exist  only  in 
the  day-time,  and  are  dried  up  during  the  niglit. 


76 


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PHYSICAL   GEOGRAPHY. 


77 


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78 


niYSICAL   GEOGTlArilY. 


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O 
O 

w 

H 

o 


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3 


w 

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1-3 


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fa 

o 
o 


m 

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03 

o 
O 


M 
O 


bM        CO 


rt 


O  C5  o  o  o 

c  m  o  o  o 

O  »0  vO  O  C3 

r-l        P5  r-t  1-1 


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a 
a 

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ti-H 

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cs 
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o    o 

O      CD 
1-1       CI 


O  O      O      O 
CJ  t-     CI     t- 


rt 


o 


c5 

g 

i 

o 

ing  Sea, 
of  Georg 

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o 

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o 

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rt 

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PHYSICAL    GEOGRAPIir. 


79 


O 

m     O     O     «D  O  O  ifl  O 

o    o    o    <r.  r-  c  -o  o 

r3    'yj    -H    c  ^  11  i-i  ^ 

►^      i-t      CO      CO  C-l  i-i  rH  i-H 

o  oe  o 

lO  o  o  o 

kf)  O  CO  r-l 

CO         cico          c/:-r5             o 
i-l  -r  i-(             ri  rH  rH                 ,H 

o"             

w 

'P,          .J- 

WH                    r^                            . 
«~"                  x       .     «     . 

O            x     -    .   .    . 
■•-•             tn                   o 

6            S                  O 

Chesapeake  Bay,  . 

New  York  Harbour, 
G.  of  St.  liawrencc, 

Caribbean  Sea, 
Atlantic, 

Ptio  de  la  Plata,     .  i 
»i 

y  Indian  Ocean, 

•S 
1 

O 

o 

< 

c 
o 

H 

o 

nwcf?.     III.— SOUTHERN  SLOPE. 

S.E.,          Texas  (United  States), 

S.,           Centre  of  United  States,    . 

S,  E. ,          N.W.  of  Mississippi  Valley, 

E.S.E.,        a.W.  of 

S.E.,          S.W.  of 

S.W.,          N.E.  of 

W.,            E.      of 

STERN  SLOPE. 

Alleghany  Mts.,     .          S.E.,          East  of  United  Statog, 

M              Pennsylvania  (U.  S.),  . 
New  York  State,    .            S.,            New  York  State, 
W.  of  Lake  Superior,    E.  k  N.E.,     British  America  and  U.  S., 

SOUTH  AMERICA. 

r— NORTHERN    SLOPE. 
Andes  near  Ecuador,!         N.,        1   Granadian  Confederation,  .  1 

II.— EA.STERN  SLOPE. 
Parime  Mountain.s,    W.,  N.,&E.,    Venezuela,    . 
Andes  of  Peru,       .            E.,            Peru.  Ecuador,  and  Brazil, 
S.E.  of  Brazil,         .        N.  .fc  E.,       Ea.st  of  Brazil,      . 

III.-SOUTIIERN  SLOPE. 
S^E.  of  Brazil,        .      S.W.  &  S.,      Brazil,  Paraguay,  <fc  La  Plata, 

"•     of     „            .       W.  ,fcS.,          „      Uruguay, 

OCEANIA. 

Australian  Alps,    .  j  W.,  N   &  S      ^^"^  ,^""*'^  ^^^Qs.  Victoria, 
1                     '        and  South  Australia, 

w 

O 

a 

D 
O 

W3 
> 

< 

o 

u 

D 
O 
02 

rn  AMERICA-cond 

Rocky  Mountains, 
Lake   Itasca  (Min- 

ncsotji),     . 
Rocky  Mountains, . 

North  of'Tcxa.s,     , 
Alleghany  Mts.,      . 

IV.-EA 

c: 

Ed 
> 

NOR' 
Rio  Grande  del 

Norte, 
Mississijipi,    .        | 

Mifwouri, 
Arkanz;:s, 
Red  River,      . 
Ohio,       . 
Ttuuessee,     . 

•       ■        •        a 

• 

ei        <S 

C       o 

m 

Magdalen  a,     .       .  1 

Orinoco, 
Amazon, 
San  Eraucisco, 

Parana,  . 

Paraguay, 

Uruguay, 

Murray,  .        .        .  1 

>• 

(a 

-^ ,                      ^ 

t 
• 

f 

Caribbean,     . 
Atlantic, .      •    -j 

Atlantic,,      .    ■! 
Australian, . 

1 

1 

80  PHYSICAL  GEOGRAPHY. 


LAKES. 

46.  Characteristics. — Lakes  are  collections  of  water 
which  are  formed  in  the  hollows  or  depressions  of  the 
surface  of  the  land,  and  may  thus  be  of  all  sizes,  from  the 
merest  pools  to  areas  of  many  thousand  square  miles. 
They  are  found  in  all  regions,  but  more  abundantly  in 
mountain  regions,  or  on  the  lower  reaches  of  great  plains. 
The  highland  lakes  generally  occupy  the  deep  narrow 
troughs  of  mountain  glens,  and  are  frequently  dis- 
tinguished for  their  picturesque  scenery;  the  lowland 
lakes  are  in  general  tame  and  unattractive,  and  closely 
connected  in  character  with  marsh  or  morass.  From  the 
limited  evaporation,  lakes  are  more  numerous  in  high 
than  in  low  latitudes ;  hence  their  frequency  and  magni- 
tude in  the  north  of  Europe,  Asia,  and  America.  On 
the  other  hand,  in  the  plains  of  South  America,  Africa, 
and  Australia,  many  lakes  of  large  area  in  the  rainy 
season  disappear  wholly  or  partially  in  the  periods  of 
arought. 

47.  Classification  of  Lakes. — Lakes  are  divided  into 
four  kinds  : — 

(1)  Those  which  both  receive  and  give  out  waters  ; 

(2)  Those  which  receive,  but  do  not  give  out  Avaters; 

(3)  Those  which  give  out,  but  do  not  receive  waters; 

(4)  Those  which  neither  receive  nor  give  out  waters. 
The  first  class  are  the  ordinary  ones,  being  either  mere 

expansions  of  a  river  in  its  course,  or  the  receptacle  of 
its  head-waters,  from  which  it  issues  as  a  distinct  river. 
The  great  Canadian  lakes  are  but  expansions  of  the  River 
St.  Lawrence,  and  Lake  Victoria  N'yanza  and  Lake 
Albert  N'yanza  are  the  basins  which  collect  the  head- 
waters of  the  Nile. 

The  second  class  are  those  which  receive  continental 
rivers,  such  as  the  Caspian,  the  Aral,  and  the  Dead  Sea. 
The  waste  of  water  by  evaporation  is  supposed  to  equal 
that  supplied  by  their  feeders.     Their  waters  are  almost 


USES    OF    LAKES.  81 

invarlal)ly  salt  or  brackish — Lake  TcLad  forming  tlio 
most  prominent  exception. 

Lake  Elton  (130  miles  in  area),  situated  in  tlie  Steppe, 
70  miles  east  of  the  River  Volga,  lias  tlie  saltest  (and 
therefore  most  buoyant)  water  in  the  world;  and  next  to 
it  is  tlie  Dead  Sea  in  Syria.  The  former  has  29  per  cent, 
of  saline  matter  in  its  waters,  the  latter  has  26^,  while  tho 
ocean  has  only  4  per  cent.  The  Dead  Sea  waters  are  exces- 
sively bitter  and  nauseous,  and  iiTitate  the  skin;  they  cannot 
support  animal  life,  excej^t  in  its  lowest  forms;  and  they  are 
so  buoyant  that  bathers  float  without  effort  on  the  surface. 

The  third  class  are  fed  by  springs  from  the  bottom 
and  maririns. 

The  fourth  class  are  also  fed  by  subterranean  springs 
and  rain;  and  evaporation  prevents  such  an  accumulation 
of  water  as  would  overflow  its  basin,  and  thus  form  a 
liver.  These  are  generally  of  small  size,  and  sometimes 
occupy  the  ci*aters  of  extinct  volcanoes. 

46.  Distribution  of  Lakes. — North  America  excels 
every  other  continent  in  the  number  combined  with  the 
mainiitude  of  its  lakes.  Its  chain  of  "fresh-water  seas" 
along  the  coiu'se  of  the  St.  Lawrence,  and  its  net- work  of 
lakes  in  the  fi\r  north,  are  without  parallel.  The  Five 
Great  Lakes  alone  cover  93,000  sq,  miles.  Lake  Victoria 
N'yanza  (230  miles  in  length  by  the  same  breadth)  is  per- 
haps the  largest  fresh-water  lake  in  the  world ;  a  pre-emi- 
nence which  was,  till  recently,  accorded  to  Lake  Superior 
in  North  America,  Sir-i-Kol,  the  source  of  the  River  Oxus 
in  Central  Asia,  is  15,600  feet  above  the  sea  (nearly  as 
high  as  Mont  Blanc),  being  the  highest  known.  The  Dead 
Sea  lies  1312  feet  below  the  level  of  the  Mediterranean. 

47.  Uses  of  Lakes. — Lakes  are  cisterns  or  reseiwoirs 
which  serve  as  regulators  of  the  discharge  of  rivei^ — pre- 
venting a  too  rapid  overflow,  which  might  cause  destructive 
inundations,  and  retaining  for  summer  use  the  superabund- 
ance of  the  winter  supplies.  They  expose  a  larger  surfaco 
to  evaporation  than  the  watei*s  of  their  respective  regions 
would  otherwise  afford,  and  thev  thus  serve  to  temper  with 

23  E  I-  " 


83 


PHYSICAL   GEOGRAniY. 


moisture  aridity  of  climate.    They  also  serve  to  purify  tlie 

rivers  which  they  feed,  by  allowing  the  sediment  or  debris 

contained  in  the  waters  they  receive  to  settle  in  their  depths. 

PuiNciPAL  Lakes  m  the  World. 


System. 


Lakes. 


PosiTio:?. 


Northern 

or 

Baltic, 

Southern 

or 
Alpine, 


Northern, 
Eastern, 

Continental 
Basin, 


Central,   | 

Northern, 
Southern, 


Northern,  . 


Southern, 
Contia''nt.d  l 
Basin,     / 


EUROPE. 

Ladoga,  Onega,  Peipus,  Suiraa; 
Enara,  &c., 

Wener,  Wetter,  Mselar,  Hielmar,  &c., 

L.  of  Geneva,  or  Lenian,  Neufcliatel, 
Lucerne,  Zurich,  Constance,  or 
Boden  See,  &c.,     .... 

JIaggiore,  Como,  Garda,  &c.,   . 

Balaton,  or  Platteu  See,  Ncusiedlcr, 

ASIA. 

Baikal,  Kosgol ;  Zaisan,    . 
Tong-ting,  and  Po-j'ang,    . 
Caspian  Sea,  and  Lake  Aral,    . 
Dead  Sea;  Van,  Urumiah, 
Hamoon,  or  Zurrah,  . 
Balkash,  Issyk-kul,  Ubsa;  Lob-nnr 
Sir-i-kol;  Tengri,  Palte;  Ko-ko-uur, 

AFRICA, 

Victoria  N'yanza,  Albert  N'yanza, 
Tanganyika,    .... 

Dembea,  or  Tznna,     . 

Alsibkah,  Melgig ;  Dcbo,  or  Dibbie 
Tchad,     

Dilolo,  Shuia,  Sliirwa,  N'yassi 
N'gami, 

NORTH  AMERICA. 

Great  Bear  Lake,  Great  Slave  Lake 
Athabasca,  Wollaston,  Beer  Lake, 
Winnipeg,  &c., 

Superior,  Huron,  Michigan,  Erie 
Ontario,  .... 

Chapala;  Nicaragua,  Leon, 

Great  Salt  Lake,  Lake  Utah,    . 

SOUTH  AMERICA. 

Lake  !Maracaybo,       .... 
Titicaca, 

Lago  dos  Patng,  .... 

Guanacache,  Silvero,  &c., 

AUSTRALLV. 

Lake  Victoria,  Torrens,  Gregory, 
Gairdner,  Blanche, 


N.  W.  of  Russia. 
Sweden. 

Switzerland. 

North  of  Italy. 
Hungary. 


Siberia,  Mongolia. 
Cluna. 

Turkestan,  etc. 
Syria,  Armenia. 
Afghanistan. 

j-  Central  Asia. 


|-  Central  Africa. 
Abyssinia. 

Barbary,  Soudan. 

Zarabesi  Basin. 


British  America. 

St.  LaAvrence  Basin. 
Mexico,  Central  Anier 

Great  Basin  of  Utah. 


N.  W.  of  Venezuela. 
Bolivia. 

South  of  Brazil. 
La  Plata^ 


South  Australia. 


EXERCISES. 


83 


Lakgest  LaKE3. 


Lake. 


I^idoga, 

Onega 

Weuer, 

Caspian  Sea, 

Aral, 

Baikal 

Ijalkash,  

Victoria  N'yanza, 
Albert  N'yaiiia,.., 

Tanganyika, 

Tchad 


Area  in 
Sq.  Miles. 


6.330 
3,400 
2,000 

140.000 
20,000 
14.S00 
.  7,000 

53,000 

9 
f 

15,000 


Lake. 


Superior 

Huron, 

Michigan, 

Eric,  

Ontario 

Great  Bear  Lake, 
Great  Slave  Lake, 
Winnipeg, 

Maracaybo 

1)03  Patos 

Titicaca, 


Area  in 
8q.  !MiIe.s 


32,000 

24,000 

20,000 

9,000 

6,300 

19,000 

12,000 

9,000 

5.000 
5.000 
3,SU0 


EXERCISES. 

1.  Point  out  the  CTeat  ■water-shed  of  Europe,  and  tliose  of  tlie 
other  conthients.  "\Vhich  is  the  highest  water-slxed  iu  the  world? 
aud  what  rivers  rise  there  ?  Name  the  great  slopes  and  river- 
systems  of  each  of  the  continents,  and  the  longest  and  sliortest 
slopes  of  each,  "What  mountains  bound  the  chief  rivcr-sj'stems  ? 
Which  systems  belong  partially  to  two  slopes  ?  Name  all  the 
rivers  that  rise  in  the  same  mountains.  Which  rivers  of  different 
systems  rise  nearest  each  other  iu  each  of  the  continents  ?  Which 
mountain-system  gives  rise  to  no  large  river  ?  Which  mountains 
in  Africa  and  Xorth  America  are  crossed  by  rivers  ?  Which  two 
African  rivers  rise  in  the  same  lake  ?  Which  continent  is  remark- 
able for  binary  rivers  ?  Point  them  out.  Which  slope  of  South 
America  has  no  lar^re  rivers  ?  Name  the  continental  rivers  of 
Europe,  Africa,  and  South  America.  Give  regions  of  elevation 
and  regions  of  depression  in  which  continental  basins  occur. 
Nam'H  the  largest  rivers  that  have  a  westerly  course.  Name 
rivers  that  have  deltas,  and  those  that  have  estuaries.  Classify 
the  rivers  according  to  their  ocean  basins.  Which  ocean  receives 
none  ?     In  what  regions  are  there  fewest  rivers  ?  and  why  ? 

2.  Which  rivers  form  boundaries  of  countries  ?  which  of  conti- 
nents? Name  the  chief  inter-tropical  rivers.  By  what  character- 
istics are  they  distinguished  ?  Name  all  the  large  rivers  of  the 
Southern  Ilemisphere.  Name  smaller  rivers  in  each  of  tlie  rivcr- 
Byatcma.     Name  the  principal  tributaries  of  the  llhinc,  Danube. 


84  PHYSICAL   GEOGRAPHY. 

Ganges,  Nile,  Mississippi,  Anicazon,  etc.  How  could  you 
pass  overland  entirely,  or  most  nearly  so,  by  water  from  the 
Baltic  to  the  Black  Sea  ? — from  the  Arctic  Ocean  to  the  Gnlf  of 
Mexico? — from  the  mouth  of  the  Orinoco  to  the  Pvio  de  la  Platp^  ? 
— from  the  West  Coast  of  Africa  to  the  East  Coast  ?  Arrange  tho 
rivers  in  the  order  of  length,  and  compare  them  with  that  of  the 
Thames  and  of  each  other.  Give  a  comparative  view  of  them  by 
means  of  a  scale  or  otherwise.  Measure  on  the  map  the  direct 
distance  from  source  to  mouth  of  the  Volga,  Vistula,  Bhine,  etc., 
and  compare  it  with  the  absolute  length.  Arrange  the  largest 
river-basins  in  the  order  of  size,  and  compare  them  with  the  area 
of  Great  Britain  or  of  the  Thames  basin  (61G0  square  miles.) 
Draw  a  map  of  each  continent  showing  the  Biver  Systems. 

3.  Which  is  the  largest  fresh-water  lake  in  each  of  the  con- 
tinents ?  Which  is  the  largest  salt  lake  in  the  world  ?  Which 
lakes  are  on  the  frontiers  of  countries?  Name  the  mountain 
systems  or  river  basins  with  which  the  lakes  in  the  Table  of 
Lakes  are  severally  associated.  Name  those  situated  in  plains. 
What  rivers  do  they  receive  or  give  out?  Into  what  seas  do 
they  discharge?  Which  lakes  of  Europe,  Africa,  and  South 
America  are  continental?  Which  continent  has  fewest  lakes? 
Which  continent  has  only  comparatively  small  ones  ?  What  is 
the  height  above  sea-level  of  Lake  Titicaca?  Compare  the  areas 
of  the  largest  lakes  with  that  of  Loch  Lomond,  the  largest 
British  lake  (45  square  miles),  and  with  each  other.  Draw  a 
Map  showing  the  Lake  Systems. 


CHAPTER  YI. 

THE  ATMOSPHEEE. 


I/! 


.J^ 


Characteristics  of  the  Atmosphere — Composition  of  Air — The 
Atmosphere  and  Light — Winds — Constant  Winds — Period- 
ical Winds — Variable  Winds — Storms — Local  Winds — Calms 
— Climate — Temperature — Snow-line — Continental  and  Mari- 
time Climates — Distribution  of  Heat — Moisture — Evapora- 
tion —  Dew  —  Fogs  —  Clouds — Bains  —  Periodical  Bains — 
Variable  Bains — Constant  Bains — Bainless  Begions — Snow 
— Avalanches  —  Glaciers  —  Icebergs  —  Hail  —  Inlluence  of 
Climate  on  Health — Causes  Affecting  Climate. 

48.  Characteristics  of  the  Atmosphere. — The  waters 
of  the  ocean  are  only  a  partial  covering  for_^the  body  of 


COMPOSITION  OP  Atii.  So 

the  eartli :  tlie  atmospliero  is  anotlicr  gi-cat  ocean,  but  of 
a  clillercnt  fluid,  wliicli  envelops,  as  an  outer  covering, 
both  sea  and  land,  and  partakes  of  all  the  motions  of  tho 
globe  itself.  It  is  supposed  to  extend  to  a  height  of  45 
or  50  miles;  and,  its  pressure  at  the  sea-level  being  equal 
to  nearly  15  lbs.  on  the  square  inch,  the  weight  of  tlio 
■whole  engirdling  mass  has  been  estimated  at  5  quad- 
rillions, 295  trillions,  900  billions  of  tons. 

But  the  air,  as  this  atmosphere  is  called,  is  highly- 
elastic,  and  becomes  less  and  less  dense  as  it  recedes  from 
the  earth's  surface.  At  the  sea-level  it  balances  a  column 
of  mercury  nearly  30  inches  high,  or  a  column  of  water 
35  feet  in  height;  but  at  a  height  of  about  12,000  feet, 
equal  to  the  higher  summits  of  the  Aljis,  it  is  only  half  the 
density;  and  at  tvdcQ  that  height,  equal  to  the  highest 
summit  of  the  Andes  or  the  higher  Himalayas,  it  is  only 
one-fourth,  and  its  pressure  %'aries  to  the  same  extent. 
Hence  the  difficulty  of  breathing,  and  the  bursting  of 
blood  from  nose,  eyes,  and  ears,  from  want  of  sufficient 
external  pressure  on  the  frame,  and  the  giddiness  and 
fainting  experienced  by  the  Alpine  traveller.  But  al- 
though at  '45  or  50  miles  the  air  will  be  of  inappreciable 
tenuity,  it  is  eveiy  way  2)robable  that  an  atmosphere, 
distinct  from  the  ether  which  occupies  all  space,  still 
exists,  and  acts  upon  meteoi'S  and  other  light-giving 
bodies  at  210  miles  above  the  sea-level.  The  pressure  is 
Qieasured  by  an  instrument  called  a  barometer,  and  tho 
temperature  by  a  thermometer;  and  these  instniments 
A-ary  with  so  much  regularity,  accordmg  to  elevation,  that 
they  are  used  for  determining  the  heights  of  mountains, 
the  mercury  in  the  barometer  falling  1°  for  every  800 
feet  of  rise,  and  the  boiling-j)oint  of  water  falling  V  for 
every  300  feet. 

49.  Composition  of  Air. — Air,  pure  and  dry,  consists 
chiefly  of  two  gases  mixed  together,  but  not  chemically 
combined,  in  the  proportion  of  about  79  parts  of  nitrogen 
to  21  of  oxygen  in  volume  (or  about  4  to  1),  but  77  of 
the  former  and  23  of  the  latter  by  weight.     With  these 


86  PHYSICAL   GEOGRAPHY. 

arc  mixed  very  minute  quantities  of  carbonic  acid  and 
carburetted  hydi'ogen,  with  a  trace  of  ammonia;  and  it  is 
never  free  of  watery  vapour,  in  greater  or  less  quantity, 
according  to  the  temperature.  This  last  ingredient,  how- 
ever, forms  no  essential  portion  of  the  air. 

60.  The  Atmosphere  and  Light. — The  air  is  the  gi-eat 

medium  of  light.     If  the  rays  fall  vertically,  only  8000 

out  of  10,000  reach  the  earth's  surface,  and  the  greater 

the  angle  of  inclination  the  greater  the  number  absorbed, 

till,  when  the  sun  is  horizontal,  only  five  rays  out  of 

10,000  reach  the  eye  of  the  spectator.     Hence  the  ease 

with  which  we  can  gaze  on  the  rising  or  the  setting  sun. 

Vapour,  whether  in  the  atmosphere  or  in  the  sea  in  the 

form  of  water,   absorbs  all  the  coloured  rays  of  light 

except  blue,  which  may  serve  to  account  for  the  blueness 

of  the  sky  and  of  the  ocean;  for,  when  above  the  vaporous 

region  of  the  atmosphere,  as  in  deserts  or  at  the  tops 

of  high  mountains,  the  sky  appears  almost  black.     But 

light  is  not  only  absorbed;  it  is  also  reflected,  refractedy 

and  dispersed.     Hence  the  rays  are  scattered  and  bent 

over  the  earth,  so  as  to  illumine  a  greater  surface  than 

they  otherwise  would;    and   thus  valleys  and  surfaces 

not  directly  exposed  to  the  sun  are  lighted.     "Without 

this,  "  shadows  would  be  as  black  as  night,  deep  valleys 

would  be  always  buried   in  darkness."      To   the   sun's 

refraction  we  owe  that  gi-ateful  dim  light  called  twilight, 

for  refraction  takes  place  till  the  sun  is  from  15°  to  20^^ 

beneath   the  horizon.     Within  the  tropics  the  sun  sets 

almost  perpendicidarly,  and  therefore  speedily;   but  in 

higher  latitudes  he  sets  more  slantingly,  and  therefore 

more  leisurely.     Hence  in  the  former  there  is  next  to  no 

twilight;  but  in  the  latter,  where  it  is  most  needed,  it  is 

long  and  gTateful.      To  the  same  causes  are  due    the 

mirage,  by  which  pellucid  lakes  appear  in  the  burning 

desert,  ^y\\^\  islets  and  groves  of  delicious  verdure  rising 

from  their  bosom;  the  rainbow,  with  its  resplendent  arch 

and  gorgeous  tints,  along  -wnlth  hcdos,  mock-suns,  the  fata, 

morgana,  and  other  optical  illusipns. 


^T^\  ;K 


y 


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t5 

a; 


WINDS.  87 

But  air  is  also  the  great  medium  of  lieat  and  moisture, 
elements  wliich  -svill  be  discussed  hereafter,  and  thcreforo 
the  most  important  agent  in  the  production  of  climate. 
At  the  same  time,  it  is  itself  the  indispensable  aliment  of 
fire,  and  of  all  animal  and  vegetable  life. 

I    ■ 
WINDS. 

51.  As  there  are  currents  in  the  ocean,  so  there 
are  currents  in  the  atmosphere,  called  winds ;  and 
they  owe  their  existence  chiefly  to  the  same  cause,  viz., 
the  inequality  of  temjierature  or  density  of  different  por- 
tions of  its  mass.  "Whenever  any  portion  is  heated,  it 
expands,  loses  its  specific  gi-avity,  and  ascends;  and  the 
colder  air  from  adjacent  parts  being  heavier,  rushes  in  to 
supply  the  vacancy  and  restore  equilibrium.  Tliis  colder 
air,  forms  an  under  or  surface  current,  and  the  rarefied 
air  in  the  higher  regions  of  the  atmosphere  to  which  it 
has  ascended,  moves  ofi",  as  an  upper  current,  in  a  con- 
trary direction.  Difierent  strata  of  the  air,  indeed,  are 
often  moA^ing  in  opposite  courses;  and  from  the  existence 
of  one  current,  we  may  generally  infer  the  existence  of  a. 
counter-cuiTcnt  in  a  difierent  region  of  the  atmosphere. 
These  currents  may  vary  in  velocity  from  the  gentlest 
zephyrs  to  the  most  violent  hurricane.  A  speed  of  7 
miles  an  hour  is  regaixlcd  as  a  gentle  air,  of  1-4  as  a  light 
breeze,  of  21  as  a  good  sailing  breeze,  of  41  a  gale,  of  Gl 
a  great  stonn,  of  82  a  tempest,  and  92  a  hurricane  pro- 
ducing universal  devastation. 

Classification  of  Winds. — Winds  are  of  three  kinds, 
viz.,  Constant,  Periodical,  and  Variable. 

1.  Constant  Winds. — The  most  remarkable  of  these  arc 
the  Trade-Winds  and  the  Polar  Winds. 

(1)  The  Trade-Winds  (so  named  from  their  favourable 
influence  upon  ti'ade  or  commerce,  as  afiected  by  naviga- 
tion), prevail  within  the  Torrid  Zone  and  a  few  degi-ees 
beyond  it.  This  zone  being  the  most  highly  heated,  the 
rarefied  air  ascends,  and  flows  ofi'  north  and  south  as 


§8  fiitsicAL  GiiOGiiAPHi?. 

iipioer  currents  ;  and  the  cool  air  from  regions  north  and 
south  rushes  in  as  under-currents,  to  preserve  the  equi- 
librium. There  are  thus  established  tAvo  sets  of  air-currents 
or  winds — two  warm,  light  north  and  south  upper  currents, 
and  two  cold  north  and  south  surface  currents.  And,  but 
for  the  earth's  rotation,  there  would  be  a  constant  north 
wind  at  the  surface  in  the  Northern  Hemisphere,  and  a 
constant  south  wind  at  the  surface  of  the  Southern 
Hemisphere.  But  these  north  and  south  winds  cannot 
partake  all  at  once  of  the  more  rapid  rotation  of  surface 
towards  the  Equator,  and  are  diverted  to  the  west,  and 
thus  become  north-east  and  south-east  winds  respectively. 
Their  limits  are  not  altogether  stationary — advancing 
farthest  to  the  north  in  the  northern  summer,  and  farthest 
south  in  our  winter.  The  trade-winds  of  the  Atlantic 
and  Pacific  are  steady  and  j^erennial,  blowing  at  a  speed 
of  10  to  20  miles  an  hoiu' ;  but  owing  to  the  inequalities 
of  surface  and  temperature  of  the  land,  they  are  modified 
into  periodical  winds  as  they  approach  the  continents. 
Hence  they  are  experienced  only  over  the  oceans,  and 
never  within  about  100  miles  of  land. 

(2)  Polar  Winds  are  constantly  blowing  within  the 
Polar  regions,  north  and  south  from  either  Pole.  But 
these  winds,  after  leaving  the  regions  of  their  birth  and 
proceeding  towards  the  equator,  are  modified,  as  already 
explained,  into  trade-Avinds. 

2.  Periodical  Winds. — (1)  Monsoons.  The  most  import- 
ant of  the  periodical  winds  are  the  Monsoons,  or  "  season 
winds,"  because  they  change  their  course  with  the  seasons 
— blowing  from  one  quarter  for  one  half  the  year,  and  from 
the  opposite  quarter  for  the  other  half.  They  prevail 
chiefly  in  the  northern  part  of  the  Indian  Ocean.  They 
are  but  the  trade-winds  modified  in  their  course  by  the 
configuration  and  relative  position  of  the  regions  which 
they  traverse.  From  April  to  October,  the  SOUth-west 
monsoon  prevails  north  of  the  Equator,  caused  by  the 
great  rarefaction  of  Southern  Asia  in  the  northern  sum- 
mer.   From  October  to  April,  the  north-east  monsoon 


Variable  winIds.  SO 

prevails,  caused  by  the  gi*eater  rarefaction  of  Africa 
during  tlie  southern  summer.  South  of  the  Equator, 
the  north-west  monsoon  blows  from  October  to  April, 
and  the  SOUth-east  monsoon  from  April  to  October. 
The  shifting  of  these  winds,  which  is  termed  "  the  break- 
in'T  of  the  monsoon,"  is  always  attended  with  violent 
storms  of  thunder  and  lightning. 

(2)  Land  and  Sea  Breezes. — These  prevail  on  almost 
every  sea-board,  but  most  notably  in  tropical  countries, 
where  they  occur  with  great  persistency  and  regularity. 
The  land-breeze  sets  in  during  the  night,  the  sea-breeze 
'diu'ing  the  day.  These  phenomena  depend  upon  the 
iinequal  temperature  of  sea  and  land  by  night  and  by  day. 
In  some  localities  these  breezes  are  limited  to  a  few  miles 
from  the  shore,  while  in  others  they  extend  over  many 
leagues — wafting  fraga-ance  to  the  passing  voyager  from 
the  spicy  gi'oves  of  Ceylon,  or  the  perfumed  shores  of 
«' Ai-aby  the  Blest."    J^a^^oU^xa.  /'■-•-    •  ■. 

3.  Variable  Winds. — ^With  the  exception  of  the  Trades, 
the  Polar  AVinds,  the  Monsoons,  and  Land  and  Sea  Breezes, 
winds  are  more  or  less  variable,  indeed  proverbially  change- 
ful. But  they  are  not  less  obedient  to  law,  although  less 
understood  from  being  partial  in  their  causes  and  operations. 
Less  pei-sistent  than  the  trades  are  the  south-west  -wdnds 
of  the  higher  latitudes  of  the  Northern  IIemis])here,  and 
the  north-west  winds  of  corresponding  latitudes  of  tlie 
Southern  IIemis[)liere.  These  may  be  considered  the 
prevailing  winds  of  these  regions.  As  the  warm  currents 
from  the  Tropics  proceed  north  and  south,  they  are  gradu- 
ally cooled  and  condensed,  and  therefore  descend  ;  but  as 
they  still  preserve  a  portion  of  the  momentum  acquired 
from  the  rapid  rotation  of  the  Equatorial  regions,  they  are 
deflected  eastwards,  and  thus  become  respectively  south- 
west and  north-west  winds. 

"  The  average  packet  voyage  from  New  York  to  Liverpool  is 
twenty-three  days,  but  the  return  voyage  forty  days ;  and 
westerly  winds  are  three  tipies  more  frequent  at  Cape  Horn  than 
easterly  ones."  ^ 


i 


90  PHYSICAL   GEOGRAPHY. 

"  In  all  latitudes  between  the  parallel  of  30°  or  35°  N.  and  30°  or 
85°  S.,  the  i^revailing  direction  of  the  wind  is  from  the  eastward  ; 
in  all  other  parts  of  the  world,  except  the  monsoon  regions,  as  far 
as  observation  has  gone,  it  is  from  the  westward." — Maim/s 
Physical  Geography. 

Within  tlie  Tropics  an  upper  west  wind  is  constantly 
flowins:  as  a  return  current  to  the  trades.  Dust  from 
West  Indian  volcanoes  lias  fallen  on  ship-board  hundreds 
of  miles  to  the  east;  and  at  the  summit  of  TenerifFe,  a 
south-west  wind  in  summer  prevails,  while  the  trade- 
wind  below  is  blowing  from  the  north-east. 

63.  Storms. — Storms  are  winds  blowing  with  great 
force  and  velocity,  and  they  may  vary  from  a  strong  gale 
at  41  miles  an  hour  to  a  hurricane  of  92,  or  even  100 
miles.  They  may  blow  for  a  considerable  time  over  the 
same  area,  and  from  the  same  general  direction,  and  are 
sometimes  accompanied  with  thunder  and  lightning.  But 
the  most  remarkable  and  destructive  storms  have  a  spiral 
or  whirling  motion;  they  twist  round  an  axis  with  extreme 
rapidity,  and  at  the  same  time  move  forAvard,  sometimes  in 
a  straight  line,  but  most  generally  in  a  curve.  They  are 
confined  to  certain  areas,  blow  only  for  a  short  time  in 
the  same  i^lace,  and  are  continually  and  rapidly  changing 
their  dii-ection.  They  are  known  as  Tornadoes,  Typhoons, 
and  Cyclones,  in  different  regions,  but  they  are  all  re- 
garded as  cyclonic  in  character.  They  are  most  violent 
within  the  Tropics,  more  particularly  on  the  borders  of 
the  Tropics  and  the  Temperate  Zones.  But  there  are 
three  well  ascertained  regions  of  these  storms,  viz.,  the 
West  Indies,  the  Indian  Ocean,  and  the  China  Seas. 

(1)  Hurricanes,  or  Tornadoes,  owe  their  violence  and 
velocity  to  electrical  influences,  and  are  accompanied  in 
general  with  thunder  and  lightning  and  torrents  of  rain. 
They  are  most  frequent  in  the  West  Indies,  about  the 
time  of  the  Equinoxos,  and  in  the  Indian  Ocean  at  the 
change  of  the  monsoons. 

(2)  Typhoons  visit  the  Chinese  seas  about  once  in  three 
years,  and  generally  from  June  to  November. 


nOT   WINDS. 


01 


(3)  Cyclones  occur  most  frequently  between  the  Equator 
and  the  Tropics,  and  near  the  Calms  of  Cancer  and  Capri- 
corn. They  sweep  round  and  round,  at  the  same  time 
moving  forward  in  a  curve,  varying  from  100  to  1000 
miles  in  diameter.  They  travel  obliquely  from  the 
]^]<|uator  to  the  Poles,  and  over  a  tract  of  3000  miles — in 
the  Northern  Hemisphere  from  right  to  left,  in  the 
Southern  Hemisphere  from  left  to  right. 

(■i)  Whirlwinds  arc  most  frequently  caused  by  tho 
meeting  of  contrary  winds,  and  assume  a  rotatory  or 
whirling  motion.  They  cause  water-spouts  at  sea,  and 
sand-pillars  in  the  desert. 

Local  Winds. — The  characteristics  and  influence  of 
these  vary  greatly  with  locality. 

(1)  Hot  Winds. — The  most  noticeable  are  those 
noxious  winds  that  originate  in  the  gi'eat  desert  of 
Sahara  in  Korth  Africa.  Their  general  name  is  the 
Simoom  (Arabic  for  hot,  poisonous)  ;  but  in  Turkey  they 


TUE   SIMOOM. 

arc  called  Samiel;  in  Egypt,  Khamsin,  (fiffu,  because 
they  continue  fifty  days) ;  in  Guinea  and  Sencgambia, 
Harmattan;  in  Italy  the  Sirocco:  and  in  Spain,  the 
Solano.  .ov/v.. 


92  t>IlYSICAL   GEOGilArnl?. 

The  Simoom  is  a  hot,  sufTocating  blast,  laden  witll  ex- 
cessively fine  particles  of  sand,  which  often  give  a  reddish 
colour  to  the  atmosphere,  and  thus  afford  forewarning  of 
its  approach.  It  withers  vegetation,  and  often  fatally 
affects  animal  life ;  the  caravan  not  unfreqnently  sinks 
beneath  the  thirst  and  fever  it  engenders,  and  leaves  the 
bones  of  the  traveller  to  whiten  amid  the  sands  of  the 
desert.  To  escape  its  baneful  efiects,  it  is  necessary  to 
lie  prostrate  on  the  ground  with  face  buried  in  the  sand 
till  the  violence  of  the  blast  has  abated. 

The  Fohn  is  a  hot  wind  that  blows  occasionally  over 
Switzerland. 

(2)  Cold  Winds. — On  the  other  hand,  the  plateau  of 
Peru,  12,000  feet  above  the  sea,  is  swept  for  four  months 
of  the  year  by  piercingly  cold  winds  from  the  snow-clad 
Cordilleras,  so  extremely  dry  as  to  prevent  putrefac- 
tion of  animal  remains.  These  are  known  as  the  Puna 
Winds,  from  the  upland  of  the  Puna,  where  they 
originate. 

The  Pampero  is  a  violent  west  wind  which  traverses 
the  pampas  of  Buenos  Ayres,  withering  vegetation  from 
its  extreme  dryness,  and  obscuring  the  air  with  whirl- 
winds of  dust,  which  it  carries  forward  to  the  Atlantic. 
It  is  a  portion  of  the  north-west  trade-winds  which  have 
crossed  the  Andes,  just  as  the  Puna  winds  are  a  portion 
of  the  south-cast  trade-winds. 

Other  cold  winds  are  the  Bora,  a  north-east  wind  from 
the  Alps  in  Istria  and  Dalmatia(at  the  head  of  the  Adriatic 
Sea),  so  violent  as  sometimes  to  overturn  men  and  horses 
at  the  plough  ;  the  Mistral,  a  violent  north-west  wind 
in  the  valley  of  the  Khone,  in  the  south-east  of  France ; 
the  GallegO,  a  formidable  north-west  wind  in  Spain  ; 
and  the  Vent  de  Bise,  a  north-east  wind  general  over 
the  northern  shores  of  the  Mediterranean. 

The  Etesian  Winds  ("annual"  or  "seasonal"  winds) 
blow  from  the  north  in  summer  over  the  Mediterranean, 
caused  by  a  flow  of  cool  air  from  the  north  to  replace  the 
highly  heated   air  that  rises  from  the  sandy  desert  of 


TEMPERATURE.  93 

Saliara  in  tlie  north  of  Africa.  But  tliey  are  variously 
moditiccl  at  ditlbreut  seasons  and  in  dilfcrent  regions. 

Calms. — There  are  three  zones  or  belts  of  Calms — viz., 
the  Equatorial  Calms,  the  Calms  of  Cancer,  and  the 
Calms  of  Capricorn. 

These  calms  are  confined  to  the  oceans,  and  fluctuate 
with  the  seasons.  The  Equatorial  belt,  which  has  an 
average  breadth  of  about  six  degi-ees,  is  not  continuous ; 
and  it  lies  generally  several  degi-ees  to  the  north  of  the 
Equator,  separating  the  two  trade-winds,  except  in  the 
Indian  Ocean,  where  it  j)resent3  a  forked  aj»pearance, 
extending  on  both  sides  of  the  Line.  The  Equatorial 
Calms  of  the  Atlantic  are  termed  by  seamen  the  Dol- 
drums. But  the  prevailing  calms  of  these  regions,  iu 
which  vessels  are  sometimes  detained  for  weeks,  are  often 
suddenly  broken  by  terrific  storms  of  thunder  and  light- 
ning, torrents  of  rain,  and  gusts  of  wind  from  every  point 
of  the  compass  in  the  course  of  a  single  hour.  The 
Calms  of  Cancer  and  Capricorn  extend  along  the  latitude 
of  30^  north  and  south,  the  extreme  limits  of  the  trade- 
winds.  The  region  of  the  Calms  of  Cancer  is  called  by 
Bailors,  "  the  horse-latitudes." 

CLIMATE. 

53.  Under  the  term  Climate  are  included  all  the  com- 
bined  elements  that  aftect  the  w^eather  of  any  district, 
and  the  principal  of  these  are  temperature  and  moisture. 

54.  Temperature. — Atmospheric  temperature  is  i)ri- 
marily  due  almost  solely  to  the  heat  of  the  sun;  and  that 
heat  is  most  intense  within  the  Tropics,  where  the  solar 
rays  are  vertical,  or  nearly  so;  for  the  higher  the  angle 
at  which  they  strike  the  eai-th,  the  greater  is  the  effect — 
just  as  the  sun  is  strongest  at  noon,  when  he  is  most 
nearly  overhead.  Hence,  within  the  Torrid  Zone  the 
heat  imparted  by  the  sun  is  equal  to  that  received  by 
all  the  rest  of  the  cai-th.  The  heat  thus  received  by  the 
earth  being  again  radiated  into  the  atmosphere,  the  lower 


94  PHYSICAL   GEOGRAPUY. 

strata  of  air  will  be  warmer  tlian  tlie  higher — the  decrease 
of  temperature  being  equal  to  1°  Fahr.  for  every  300  or 
350  feet  of  altitude.  Thus,  there  are  two  gi^eat  causes 
similarly  affecting  temperature,  viz.  : 

(1)  Latitude,  or  distance  from  the  Equator;  and, 

(2)  Altitude,  or  height  above  the  level  of  the  sea. 

It  is,  therefore,  nearly  the  same  whether  we  proceed 
from  the  Equator  to  the  Poles,  or  ascend  vertically  into 
the  atmosphere,  as,  for  example,  in  climbing  a  lofty 
mountain.  In  both  cases  we  reach,  at  last,  the  region  of 
perpetual  snow,  the  lower  edge  of  which  is  called  the 
snow-line — at  the  sea-level  at  the  Poles,  at  the  height  of 
16,000  feet  at  the  Equator.  And  in  the  intermediate 
s^^aces,  in  each  case,  will  be  correspondmg  zones  of  tem- 
perature, and,  therefore,  of  animal  and  vegetable  life — 
the  same  phenomena  being  observable  in  the  ascending 
areas  engirdling  a  lofty  mountain  as  in  traversing  the 
6000  miles  from  the  Equator  to  the  Poles.  At  the 
base  of  the  mountain  (if  Avithin  the  Tropics)  will  be 
found  all  the  characteristics  of  the  Torrid  Zone;  mid- 
way up  those  of  the  Temperate;  and  at  the  summit 
those  of  the  Frigid  Zones.  In  tropical  America,  Guay- 
aquil on  the  coast  suffers  from  intense  heat  all  the  year 
round;  Quito,  10,000  feet  higher,  enjoys  per^^etual  sjmng; 
and  the  summits  of  the  neighbouring  Andes,  6000  feet 
higher  than  Quito,  have  eternal  winter. 

Snow-line.  —  The  height  of  the  snow-line  varies  not 
only  with  latitude,  but  also  Avitli  the  situation  as  regards 
exposure  to  the  sun  and  rain-bearing  winds,  the  degree 
of  humidity  of  the  climate,  and  other  causes,  so  that  no 
general  rule  can  be  laid  down.  But  it  is  about  4000 
feet  higher  on  the  north  than  on  the  soiith  side  of  the 
Plimalayas,  owning  chiefly,  on  the  one  hand,  to  the  great 
dryness  of  the  vast  table-lands  of  Central  Asia,  which 
increases  the  radiation  of  the  solar  heat,  and  therefore 
the  evaporation;  and  on  the  other  hand,  to  tlie  moisture 
conveyed  to  the  southern  slope  by  the  warm  winds  from 
the  Indian  Ocean.    Thus,  millions  of  men  occupy  populous 


CONTINENTAL   AND    MAKITniE    CLIMATES. 


95 


to^vTis  in  a  region  which,  but  for  this  arrangement,  would 
have  been  buried  under  snow  tlie  wliole  year.  Tlie  snow- 
line is  also  higher  in  the  interior  of  continents  than  near 
the  coasts,  and  higher  on  the  east  tlian  on  the  west  sides. 
It  is  highest,  not  at  the  Equator,  but  near  the  Tropics, 
where  the  summer-heat  is  greatest — the  day  being  tlicro 
13}  lioiu's  at  the  longest,  while  never  more  than  12  at 
the  Equator. 

None  of  the  British  mountains  reach  the  snow-line,  hut  Ben 
Kevis  is  supposed  to  bo  witliin  150  feet  of  it;  and  the  proprietor 
of  Ben  Wy  vis  once  held  his  land  on  condition  that  he  presented 
to  the  superior  a  suow-ball  from  the  mountain  whenever  required. 

Height  of  Snow-Line  in  different  Latitudes. 


SpitzbcrgPTi, 
Nortli  Cuiie, 
Sulitclina  (Norwa)-), 
Kainstchatka,    . 
Ooiialaska( Aleutian  ^ 
Islcs),     .        .J 
Altai, 
Alps, 

Caucasus,  . 
Pyrenees,  . 
Rocky  Mountains,    . 
ifouut  Etna, 
Sierra  Nevada(Spain), 


N. 

Height  1 

Lat. 

in  Feet,  j 

TS' 

0 

7i* 

2,400 

GT 

3,S35 

uoy 

5,249 

53}° 

3,510 

50" 

7,034 

40* 

8,SS5 

43* 

11,003 

42i' 

S.OJO 

43' 

12,4(57 

37  r 

9,500 

37" 

11,200 

North  ITimalayas, 
Soutli  Himalayas, 
Abyssinian  Mis., 
Purac(5  (Andes), 


Andes  of  Quito, 
Bolivia, 


»» 


Cliili, 


Stmits  of  Magellan, 
South  Georgia,  . 


X. 

Height 

Lat. 

in  I'eet. 

29' 

19,r.C0 

28° 

15,500 

13" 

14,005 

2r 

15,381 

S.  Lat. 

0° 

15,R20 

10* 

17,717 

la' 

20,07'J 

?,r 

14,730 

42.^° 

C,010 

53. i° 

3,707 

54  r 

0 

55.  Continental  and  Maritime  Climates. — The  ocean, 
radiating  its  wannth  much  more  slowly  than  the  land, 
and  its  area  being  three  times  greater,  it  becomes  a  vast 
storehouse  of  heat,  which  (independently  of  evaporation) 
its  waves,  tides,  and  currents  distribute  over  the  cdobe. 
By  these,  as  well  as  by  winds,  it  tends  to  equalize  the 
temperature  of  the  land;  hence  islands  and  seaboards 
possess  a  more  equable  climate  than  the  interior  of  con- 
tinents— less  cold  in  winter,  and  less  hot  in  summer. 
The  British  Isles  are  thus  said  to  possess  a  maritime  or 
insular  climate,  the  interior  of  Germany  and  Ptussia  a 
continental  climate.  Hence,  also,  the  greater  extension 
of  laud  in  the  Northern  IIemi.'^;>here  confers  upon  it  t^ 


96  PHYSICAL   GEOGRArilY. 

continental  climate  :  the  greater  expanse  of  ocean  in  the 
Southern  imparting  more  of  a  maritime  climate.  For 
the  same  reason,  the  snow-limit*  in  the  Southern  Hemi- 
sphere is  10°  nearer  the  Pole  than  in  the  Northern;  in 
the  latter  being  nearly  coincident  with  the  parallel  of 
30^  in  the  former,  with  that  of  40°. 

London,  nearly  2°  north  of  Paris,  can  rear  plants  in 
the  open  air  which  must  be  sheltered  in  the  green-houses 
of  Paris;  the  Shetland  Isles,  10°  still  farther  north,  have 
a  winter  temperature  higher  than  that  of  Paris,  and  equal 
to  that  of  London;  the  myrtle  flourishes  as  well  in  the 
north  of  Ireland  as  in  Portugal;  and  the  northern  shores 
of  the  Black  Sea  are  frozen  in  winter,  while  those  of  the 
British  Isles  are  perfectly  clear  of  ice. 

56.  Distribution  of  Heat. — The  Torrid  Zone  has  not 
only  the  highest  temperature,  but  it  has  little  variation 
of  temperature  thi'oughout  the  year,  the  sun  being  ver- 
tical, or  nearly  so,  all  the  year  round,  and  there  being 
little  difference  in  the  length  of  day  and  night.  The 
Temperate  Zones  are  distinguished  for  their  regular  suc- 
cession of  climatic  changes,  which  determine  the  four 
seasons,  Spring,  Summer,  Autumn,  and  Winter,  with 
great  differences  of  temperature.  The  Frigid  Zones  have 
only  two  seasons — one  long  winter  of  extreme  cold,  and 
a  short  summer  of  great  heat.  Chiefly  from  the  unequal 
distribution  of  land  and  water  and  difference  of  eleva- 
tion, the  heat  does  not  decrease  everywhere  at  equal  pace 
with  tlie  increase  of  latitude.  The  Southern  Hemisphere 
decreases  in  temperature  with  latitude  much  more  rapidly 
than  the  Northern,  and  is,  on  the  average,  3  J°  colder.  The 
Warmth  Equator  is  not  coincident  with  the  Geographical 
Equator,  but  runs  irregularly,  for  the  most  part,  a  little 
to  the  north  of  it,  and  its  mean  temperature  is  80°. 

In  the  same  way,  lines  of  equal  heat  (called  isotherms) 
are  irregular  wavy  lines,  and  by  no  means  parallel  to  each 
other  or  to  the  parallels  of  latitude.     Thus  the  isotherm 

*  The  snow-limit  is  tlie  line  on  the  equatorial  side  of  which 
Buow  never  falls  at  the  level  of  the  sea. 


DEW.  97 

of  30°,  that  is,  of  constantly  frozen  ground,  in  tlie  Northern 
Hemisphere,  passes  through  the  south  of  Hudson's  Bay, 
south  point  of  Greenhmd,  to  the  north  of  North  Cape, 
through  the  White  Sea,  Lake  Baikal,  and  Kamtchatka. 

The  temperature  diminishes  more  rapidly  northwards 
in  North  America  and  Eastern  Asia  than  in  Europe.  In 
the  Northern  Hemisphere  the  western  coasts  are  warm, 
and  the  eastern  cold;  in  the  Southern  Hemisphere  the 
eastern  are  ^varm,  and  the  western  cold.  This  is  due  to 
the  ocean  currents  and  winds,  already  described.  The 
coldest  region  in  the  world  is  in  Siberia,  stretching 
from  the  north  of  Lake  Baikal  north-eastwards  into  the 
Northern  Ocean,  in  the  form  of  a  long  ellipse.  At 
Yakutsk,  on  Lake  Baikal,  the  gi'ound  is  frozen  to  a  depth 
of  382  feet.  The  hottest  region  of  the  globe  is  on  both 
sides  of  the  Red  Sea — from  the  Sahara  through  Nubia 
and  the  middle  of  Arabia  to  the  Persian  Gulf.  The  mean 
temperature  of  the  North  Pole  is  2^,  of  the  Equatoi',  80^, 
and  of  the  whole  eai-th,  58\ 

MOISTURE. 

57.  Evaporation. — Moisture  is  always  present  in  the 
atmosphere  in  the  form  of  invisible  vapour;  and  the 
warmer  the  air,  the  greater  is  its  capacity  for  moisture. 
Tliis  moisture  is  supplied  by  evaporation  from  the  smface 
of  land  and  water;  especially  the  latter,  and  on  account 
of  its  larger  area,  mamly  from  the  ocean.  This  evapora- 
tion, depending,  as  it  does,  upon  the  solar  heat,  is  gi-eatest 
in  the  Ton-id  Zone,  where  it  is  estimated  that  16  feet  in 
average  depth  of  water  are  raised  in  a  year  from  the 
surface  of  the  sea.  The  force  for  making  and  lifting 
vapour  from  an  area  of  one  acre  is  ecpial  to  30  horse- 
power, and  for  the  whole  area  of  the  earth  800  times 
gi-eater  than  all  the  ^vater-power  of  Europe.  The  whole 
of  this  mighty  mass  of  water  is  again  precipitated  upon 
the  eai-th  as  dew,  rain,  snow,  or  liail. 

58.  Dew. — Dew  is  one  of  the  results  of  the  condensa- 
23  E  ti 


08  PHYSICAL   GEOGRAPHY. 

tion  of  vapour.  After  a  warm  day,  wlien  the  earth  has 
been  heated  by  the  sun,  and  when  evenmg  sets  in,  the 
surface  loses  its  caloric  or  heat  by  radiation  into  the 
atmosphere.  It  is  only  good  radiators,  however,  that  do 
so,  such  as  grass,  glass,  painted  wood,  etc.,  whereas  metal, 
sand,  gi-avel,  rock,  etc.,  which  are  bad  radiators,  do  not. 
These  radiating  bodies  become  cooled,  and  so  does  the  air 
immediately  in  contact  with  them.  This  au'  can  no  longer 
retam  the  same  amount  of  moisture,  and  deposits  a  por- 
tion upon  the  radiating  surfaces  in  the  bright  glittering 
globules  called  dew.  The  degree  of  temjDerature  requu^ed 
to  produce  this  deposition  is  called  the  dew-2yoint ;  and  if 
the  atmosphere  has  been  well  saturated  by  the  previous 
day's  heat,  only  a  slight  depression  of  temperature  is 
required.  Hence,  in  tropical  countries,  the  dcj^osition  of 
dew  is  most  copious,  and  largel}''  compensates  for  the 
absence  of  rain  by  its  refreshing  and  cooling  moisture. 
And,  by  a  wise  provision,  it  is  only  grass  and  plants  that 
requii'e  it  most  that  are  thus  supjDlied,  for  the  gravel  and 
rock  receive  none.  Besides  a  warm  day  preceding  to 
provide  vapour  in  the  atmosphere,  the  air  must  be  clear 
to  permit  a  free  radiation,  and  calm  to  allow  the  cooled 
air  to  remain  in  contact  with  the  radiator;  and  no  tree  or 
other  object,  not  even  a  cobweb,  must  overshadow  the 
radiating  body,  else  radiation  is  effectually  intercepted. 
At  two  or  three  inches  above,  the  chilling  is  diminished 
to  one-half,  and  at  six  feet  to  one-twentieth — the  body 
itself  being  generally  4°  lower  than  the  surrounding  aii\ 
The  air,  by  continually  parting  with  its  caloric,  may  fall 
below  the  freezing  point,  and  the  moisture  may  be  de- 
posited in  the  form  of  hoar-frost,  which  is  just  frozen  dew. 
69.  Togs. — Fog  or  mist  is  formed  by  currents  of  moist 
air  coming  in  contact  with  the  colder  surface  of  the 
earth,  and  condensing  the  contained  moisture  into  the 
visible  form  of  fog  or  mist.  Mountain  sides,  river 
valleys,  the  sea-coast,  and  cold  countries  are  favourable 
to  the  formation  of  fogs;  and  it  is  the  vapour  produced 
from  the  warm  waters  of  the  Gulf  Stream,  condensed 


cirhus  or  summer  cloud.  99 

by  the  cold  of  tlio  Arctic  Current  and  the  nortLern  ice- 
bergs, that  gives  rise  to  the  dense  fogs  of  Newfoundkmd. 

60.  Clouds. — If  instead  of  being  condensed  near  the 
earth,  as  in  the  case  of  fogs  and  mists,  the  vapour  is  con- 
densed at  some  considerable  elevation,  the  result  is  a 
cloud.  It  remains  for  a  longer  or  shorter  period  sus- 
pended in  the  aii'  motionless,  but  most  frequently  moved 
by  the  winds;  but  why  it  does  not,  when  thus  condensed, 
immediately  fall  to  the  gi-ound,  has  not  been  satisfactorily 
explained.  Some  clouds  indeed  remain  stationary,  at- 
tached to  a  mountain  summit,  as  at  Mount  Pilate  in 
Switzerland,  Table  jNIountain  at  Cape  of  Good  Iloj^e,  and 
elsewhere,  where  the  cloud  is  the  condensation  formed  by 
the  cold  mountain  side;  and  as  fast  as  a  jiortion  is  drifted 
away  by  the  wind,  another  is  formed,  which  gives  the  cloud 
an  appearance  of  permanence.  But  the  clouds  are  generally 
in  motion,  different  strata  of  them  indeed  often  moving 
in  different  dii'ections  at  the  same  time.  Their  rate  of 
motion  is  not  unfrequently  from  70  to  100  miles  an  hour, 
although,  from  their  great  height,  their  apparent  speed  is 
much  less.  The  cloud  region  of  this  country  is  from 
2000  to  6500  feet  high,  with  a  thickness  of  2000  to  3000 
feet;  but  in  the  trade-wind  region,  it  ranges  from  3000 
to  5000,  where  also  the  cloud-region  is  higher  over  sea 
than  over  land,  whereas  in  other  regions  it  is  the  reverse 
— higher  over  land  than  over  sea,  and  the  higher,  too,  the 
further  inland. 

Classification  of  Clouds. — Clouds  are  gi-ouped  into 
seven  classes — three  primary,  and  four  secondary  or  com- 
pound forms,  viz. : — 

Primary. — (1)  Cirrus,  or  Curl  Cloud;  (2)  Cumulus, 
or  Summer  Cloud;  (3)  Stratus,  or  Fall  Cloud. 

Compound. — (4)  Cirro-cumulus ;  (5)  Cirro-stratus  ; 
(G)  Cumulo-stratus ;  and  (7)  Nimbus,  or  Ptain  Cloud. 

(1)  The  Cirrus,  or  Curl  Cloud,  is  the  name  applied  to 
light  fleecy  clouds,  and  is  so  named  from  the  beautiful 
curl  their  parts  assume.  Curl  clouds  are  the  highest  of  all 
clouds,  being  not  less  than  three  miles  in  height,  and 


100 


PHYSICAL   GEOGRAPHY. 


often  five  or  six.  They  are  therefore  the  lightest  clouds, 
and  are  supposed  to  consist  of  minute  ice-crystals,  or  very 
fine  snow-flakes.  They  arrange  themselves  in  parallel  or 
divergent  bands,  arranged  at  the  Equator  nearly  from 
nortli  to  south,  but  in  this  country  from  north-west  to 


CIRRUS. 

south-east.  They  form  what  are  known  as  "  mackerel- 
skies,"  and  it  is  amongst  them  that  halos  and  mock-suns 
are  visible.  When  they  appear  after  a  day  of  north  wind, 
it  is  a  sure  sign  of  api)roaching  wet  and  stormy  weather. 
They  are  suj)posed  to  be  the  heads  of  columns  of  vapoiu* 
precipitated  so  soon  as  they  reach  a  certain  elevation. 


CUiMULUS. 


(2)  The  Cumulus,  or  Summer  Cloud,  is  the  massy 


NIMBUS  OR  aAVV  cloud. 


101 


ficecy  cloild  of  tlie  lower  and  middle  sky,  arranged  in 
rounded  and  ftmtastic  shapes,  and  often  presenting  the 
appearance  of  a  range  of  snowy  mountains.  It  is  formed 
after  sunrise,  gi-adually  increases,  and  rises  higher  as  the 
day  advances,  being  carrietl  upwards  by  the  ascending 
columns  of  heated  air,  but  disappears  towards  evening  as 
the  ascending  column  gives  way  to  a  descending  column, 
when  the  temperature  falls.  Fleecy  outriders  from  its 
sides  betoken  speedy  rain. 

(3)  The  Stratus,  or  Fall  Cloud,  is  the  heavy  bank  or 
layer  of  vapour  or  cloud,  which  rests  upon  the  horizon, 
which  is  formed   at   night-fall    (hence  the   name),   ar.d 


STRATUS. 

which  vanishes  on  the  approach  of  day.  It  is  the  cloud 
of  the  night,  as  the  cumulus  is  that  of  the  day.  Closely 
allied  with  it  are  mists  and  fogs,  and  it  is  formed  in  the 
same  way,  "viz.,  the  condensation  of  the  vapour  of  low 
river-flats  and  valleys.  If  not  dissipated  by  the  morning 
warmth,  it  may  become  permanent,  and  pass  into  rain 
cloud. 

(4,  5,  and  G)  The  Cirro-cumulus,  Cirro-stratus,  and 
Cumulo-stratus  are  but  combinations  of  two  of  these 
simple  forms,  and  need  not  here  be  described. 

(7)  The  Nimbus,  or  Rain  Cloud,  called  also  Cumulo- 
cirro-stratus,  presents  a  leaden  grey  ajipearancc,  and, 
when  dischaiging  rain,  a  ragged  and  frayed  uudcr-suiface. 


102  wi^^sicAi;.  OEOGrvAriiV. 

It  is  generally  low,  from  1000  to  5000  feet,  and  is  formed 
by  tlie  cumulus  drifting  under  the  cin-o-stratus,  whence 
is  formed  the  true  rain  cloud,  with  its  mass  of  saturated 
vajDOur. 

PvAINS. 

61.  The  annual  precipitation  of  rain  would,  on  an  aver- 
age, cover  the  globe  to  the  depth  of  five  feet.  This  would 
give  186,247  cubic  miles  of  Avater,  or  760  billions  of  tons 
for  the  total  annual  rainfall  over  the  globe.  And  to  hoist 
all  this  mass  high  into  the  air,  to  transport  it  over  the 
globe,  and  deposit  it  again  at  the  right  places,  at  the 
right  times,  and  in  due  proportion,  is  the  province  of  the 
winds.  They  are  the  machinery  employed  to  work  the 
grand  water-system  of  the  globe. 

Distribution  of  Rain. — Moist  warm  air  is  like  a  wet 
sponge.  A  cold  air  meeting  it  condenses  its  moisture  into 
clouds  (or  visible  vapour),  and  still  further  into  heavy 
drops  which  fall  as  rain,  just  as  the  pressure  of  the  hand 
squeezes  the  water  from  the  sponge.  The  winds  comming- 
ling the  cold  and  warm  strata  of  air,  rain  will  be  most 
frequent  where  the  winds  are  most  variable,  that  is,  in 
the  Temperate  Zones,  and  least  frequent  where  the  winds 
are  constant  and  of  equal  temperature,  that  is,  in  the  Torrid 
Zone.  But  from  the  greater  evaporation,  and  the  greater 
capacity  for  moisture  of  the  heated  air  in  inter-tropical 
regions,  the  rains  are  there  most  abundant,  and  they  de- 
crease in  quantity  as  we  advance  into  higher  latitudes. 
From  the  island  of  Hayti  in  the  West  Indies  to  Finland 
in  the  north-west  of  Russia,  the  decrease  ranges  from  150 
to  13  inches.  But  though  the  rainfall  of  the  Tropics  is 
the  most  abundant,  the  number  of  rainy  days  is  fewer 
than  in  high  latitudes — being  in  the  latter  distributed 
irregularly  over  the  whole  year.  Thus,  at  the  Equator, 
the  whole  rainfall  of  95  inches  is  confined  to  78  or  80 
days;  but  at  St.  Petersburg  the  fall  of  17  inches  is  dis- 
tributed over  169  days. 


DISTRIBUTION    OF    RAIN.  103 

The  trade-winds  arc  the  gi'cat  evaporators ;  and  as 
the  south-cast  trades  blow  over  three  times  as  mucli 
water  as  the  north-cast  ones,  the  rains  they  convey  to 
the  Northern  Hemisphere  are  half  as  much  again  as 
those  in  the  Southern  Hemisphere :  a  providential 
arrangement  for  the  Avatering  and  fertilizing  of  the  land 
of  the  globe,  which  lies  so  largely  on  its  northern  side. 
In  the  Noi-th  Temperate  Zone  the  mean  annual  rainfall 
is  37  inches ;  in  the  South  Temperate,  26  inches.  Tho 
rainfiill  is  always  greater  near  the  coast  than  in  inland 
regions — the  air  losing  its  humidity  by  degrees,  as  it 
passes  into  the  interior.  From  the  moist  and  verdant 
Ireland  eastwards  to  the  rainless  Desert  of  Gobi  in 
Central  Asia,  we  find  an  almost  regular  gradation  from 
the  extreme  of  humidity  to  that  of  di'ought. 


East  of  Ireland,  .  .  .  20S 
Netherlands.  .  .  .170 
England,  France,  N.  Germany,  155 


Rainy  days    -  Rainy  days 

per  annum.  per  annniii. 

Basin  of  the  Volga,  .  90 
Interior  of  Siberia,  .  GO 
Desert  of  Gobi,    .         .       0 


Mountains  are  the  great  condensers  of  moisture.  Their 
cold  summits  an-est  the  passing  vapour,  and  transform  it 
into  clouds,  which  hang  about  their  summits  till  they 
descend  in  rain,  and  pour  in  numerous  torrents  down 
their  sides.  Thus  every  mountain-system  becomes  the 
centre  of  a  system  of  irrigation  to  the  surrounding  regions; 
and  rugged  mountainous  countries,  like  Scotland  and 
Switzei-iand,  are  the  wettest.  The  side  of  a  chain  ex- 
posed to  the  moist  wind  receives  a  much  larger  share 
than  the  opposite.  Thus,  the  Scandinavian  Alps,  with 
their  lofty  frozen  heights,  condense  the  moisture  of  tho 
south-west  winds  from  the  Atlantic,  and  cause  a  precipi- 
tation on  their  Norwegian  side  about  four  times  greater 
than  that  in  Sweden,  on  their  eastern  side.  The  same 
wind  may  carry  rain  to  one  side  of  a  mountain,  and  clear 
cold  weather  to  the  other ;  and  thus  mountains  may  not 
only  separate  countries,  but  climates.  For  a  similar 
reason  lofty  plateaux  are  diy — the  winds  being  robbed  of 


101  PitYSTCAt  GilOGIlAPHT. 

tlicir  moistiirc  on  tlicir  way  up  tlio  ascending  slopes. 
Thus,  Madrid,  in  the  centre  of  the  plateau  of  Spain, 
receives  only  10  inches  of  rain;  being  at  least  100  less 
than  the  west  coast  of  Portugal  in  the  same  latitude. 

Classification  of  Rains. — Eains  being  so  closely 
dependent  upon  winds,  are,  like  them,  divided  into 
Periodical,  Variable,  and  Constant,  whilst  in  some 
regions  they  are  altogether  absent. 

( 1 )  Periodical  Rains. — The  Periodical  Pains  occur  within 
the  Tropics,  where  the  year  is  divided  into  two  seasons— 
"  the  rainy"  and  "the  dry."  The  rains  follow  the  apparent 
course  of  the  sun,  prevailing  north  or  south  of  the  Equa- 
tor according  as  the  sun  is  vertical  in  these  regions.  In 
general  terms,  the  rainy  season  may  be  said  to  extend,  on 
the  north  of  the  Equator,  from  April  to  October,  and  the 
dry  from  October  to  April,  and  the  reverse  of  this  to 
characterise  the  south  side  of  the  Equator.  The  periodicity, 
however,  depends  greatly  upon  distance  from  the  Equator, 
the  configuration  of  the  land,  and  similar  causes ;  but  in 
the  same  localities  the  rains  recur  with  the  greatest  regu- 
larity. From  5'^  to  10*^  north  and  south  of  the  Equator, 
two  rainy  seasons  and  two  dry  ones  occur  annually, 
because  the  sun  crosses  the  Equator  twice  in  the  year. 
The  rains,  although  very  heavy,  are  not  contmuous  dur- 
ing the  w^et  season ;  they  never  fall  at  night,  and  during 
the  day  only  from  noon  till  4  or  5  o'clock,  when  it  pours 
in  torrents.  During  the  dry  season  no  rain  falls  for 
months — the  want  of  rain  being  compensated  for  by  copious 
nightly  dews.  India  and  other  countries  around  the 
Indian  Ocean  have  their  seasons  regulated,  not  by  the 
course  of  the  sun,  but  by  the  monsoons.  The  south- 
west monsoon  waters  the  west  coast  of  India,  and  the 
north-east  monsoon  the  east  coast ;  for  the  Ghauts  on 
either  side  of  the  peninsula  abstract  the  moisture  from 
the  respective  winds  which  they  face,  and  render  them 
dry  and  rainless  to  the  land  on  the  ojoposite  side. 

(2)  Variable  Rains. — Variable  rains  are  extra-tropical. 
They  occur  throughout  the  whole  year  in  the  Temperate 


RAINLESS   REGIONS.  105 

Zouch;  but,  on  the  "svliolo,  nortli  of  the  Tropics,  most 
abundantly  in  winter.  England  has  eight  times  more  rain 
in  winter  than  in  summer.  The  countries  around  the  i\Iedi- 
terranean,  speaking  generally,  are  regions  of  winter  rains ; 
those  of  "Western  Europe  of  autumn  rains ;  east  of  the 
hitter  (keeping  north  of  the  Alps  and  Carpathians),  on- 
wards to  the  interior  of  Sibei'ia,  is  the  province  of  summer 
rains.  The  south-west  winds  of  Europe  are  laden  with 
moisture  from  the  Atlantic  (or  IMediterranean),  while  the 
north-east  winds,  overland  from  high  latitudes,  are  cold 
and  dry.  But  in  North  America  north-east  winds  bring 
stonns  of  rain  in  spring  and  autumn.  In  both  Temper- 
ate Zones  the  western  coasts  are  the  moister,  from  their 
exposure  to  westerly  winds  from  the  ocean ;  but  in  the 
Torrid  Zone,  the  eastern  are  the  moister,  from  their  ex- 
posure to  the  trade-^vinds. 

(3)  Constant  Rains. — "Wliilst  in  the  region  of  the  trades 
at  sea  there  is  scarcely  a  drop  of  rain,  in  the  Zone  of 
Equatorial  Calms  and  Variable  Winds  there  is  almost 
constant  precipitation,  accompanied  with  frequent  thun- 
der-storms of  gi'eat  violence.  The  rain  is  there  so 
abundant  that  the  fresh  rain-water  has  been  skimmed 
from  the  surface  of  the  sea.  A  portion  of  this  belt,  near 
the  Cape  Verde  Islands,  is  known  to  sailors  as  "  the  rainy 
sea."  The  countries  remarkable  for  their  heavy  and  con- 
tinuous rains  in  the  New  World,  are  Brazil,  Guiana, 
West  Indies,  Central  America,  and  shores  of  the  Gulf  of 
Mexico;  and  in  the  Old  World,  Guinea,  Senegambia, 
Eastern  Africa,  India,  and  the  Eastern  Archipelago.  The 
greatest  rainfall  recorded  was  in  the  Khasia  Mountains 
in  Bengal — viz.,  GOO  inches  per  annum,  and  sometimes 
30  inches  fjill  in  twenty-four  hours. 

Rainless  Regions. — In  the  Northern  Hemisphere  are 
immense  tracts  of  land  destitute  of  rain,  forming  a  belt 
around  the  globe  along  or  near  the  Northern  Tropic,  and 
inteniiptcd  only  by  mountain-ranges  at  one  point,  viz.^ 
at  the  junction  of  the  Himalayas  and  Hindoo  Koosh.  It 
comprises,  in  the  New  World,  the  plateau  of  IMcxico, 


103  niYSTCAL   GEOGRAPHY. 

with  parts  of  Guatimala  and  California ;  and  in  tlie  Old 
World,  tlio  Desert  of  Sahara,  Egypt,  Arabia,  Persia, 
Beloochistan,  the  Desert  of  Shamo  or  Gobi,  and  the  table- 
land of  Tibet  and  Mongolia.  They  measure  in  all  5|- 
million  square  miles.  South  of  the  Equator  the  only 
rainless  district  is  the  Desert  of  Atacama,  a  narrow  strip 
of  coast,  several  hundred  miles  in  length,  in  Peru  and 
Bolivia,  crossed  at  right  angles  by  the  Southern  Tropic. 
In  some  of  these  regions  a  drop  of  rain  never  falls,  whilst 
in  others  it  falls  only  at  long  intervals  and  in  small  quan- 
tities. A  fall  of  rain  (twice  or  thrice  in  a  century  per- 
haps) is  long  remembered  as  a  remarkable  event.  On 
the  Peruvian  coast,  the  rains,  driven  by  the  trades,  are 
intercepted  by  the  Andes  ;  in  the  Sahara,  the  heated  air, 
from  its  immense  sandy  area,  cannot  condense,  but  rather 
dissipates  the  vapour  of  winds  blowing  into  it ;  the  other 
districts  are  chiefly  plateaux,  from  which  the  moisture 
has  been  intercepted  by  the  acclivities  leading  up  to 
them,  or  the  heights  which  wall  them  in,  or  are,  besides, 
situated  in  the  range  of  a  dry  north-east  wind. 

SNOW. 

62.  Snow  is  the  frozen  moisture  which  fiills  when  the 
atmosphere  near  the  surface  of  the  earth  is  near  or  below 
32°,  the  freezing  point  of  water.  It  is  composed  of  crys- 
tals, generally  in  the  form  of  six-pointed  stars,  of  which 
about  1000  kinds  have  been  observed,  and  reduced  to  five 
principal  varieties.  They  are  often  of  rare  and  exquisite 
beauty,  and  those  of  the  same  fall  of  snow  are  generally 
similar  to  each  other;  but  this  symmetry  of  form  is  only 
to  be  seen  in  perfection  in  high  latitudes.  Within  the 
snow-limit  (about  30°  North  Latitude  and  40°  South 
Latitude)  snoAv  at  the  sea-level  is  entirely  unkno"vvnj  else- 
where it  falls  only  during  winter;  and  it  increases  in 
frequency  and  amount  as  we  advance  into  higher  latitudes 
or  to  greater  elevations.  It  contains  ten  times  its  bulk 
of  air,  and  being  therefore  a  bad  conductor  of  heat,  forms 


AYALAXCnES. 


107 


an  admirable  covering  for  the  cartli,  protecting  vegetation 
from  the  severity  of  frosts,  and  preventing  a  too  freo 
radiation  from  tho  soil.  Hence  it  frequently  happens 
that,  in  seasons  of  extreme  cold,  the  soil  is  40°  warmer 
than  the  surface  of  the  snow  above  it.  It  is  in  higli 
latitudes  that  the  value  of  the  "snow-blanket"  is  most 
felt  and  appreciated. 


'^'••^■■i-'iU; 


SNOW  CRYSTALS. 

Phenomena  of  Snow. — From  the  long-continued  ac- 
cumulations of  snow,  partially  thawed  and  compressed 
on  the  summits  of  high  mountains,  originate  the  various 
phenomena  of  avalanches,  glaciers,  and  icebergs. 

(1)  Avalanches  are  immense  masses  of  snow,  or  snow 
and  ice,  frequently  detached  from  the  steep  slopes  of  snow- 
clad  mountains,  such  as  the  Alps,  and  precipitated  into 
the  phiLiis  or  valleys  below.  Thoy  rush  down  with  fear- 
ful  rapidity  and  violence,   overwhelming   and   burying 


lOS 


rnYSICAL   GEOGRAPHY. 


farm-liouses  and  villages  with  their    inhabitants,   corn- 
fields, vineyards,  and  plantations. 

(2)  Glaciers  are  immense  masses  of  ice  formed  above 
the  snow-line,  which  collect  in  the  valleys  and  ravines  of 
high  mountains,  and  move  downwards  till  they  come 
below  the  snow-line,  and  sometimes  even  far  down  into 
the  cultivated  region,  when  they  melt  and  disappear  in  a 
stream  of  water.  They  bear  much  the  same  relation  to 
the  snow-fields  above  them  that  icicles  do  to  the  snow- 
covered  roof  of  a  house.  They  have  the  general  appearance 
of  torrents  or  cataracts  suddenly  arrested  and  congealed 
by  intense  frost.  The  ice  itself  is  of  a  blue -veined 
structure,  due  to  great  pressure;  but  although  rigid  in  ap- 
pearance, it   is  of   a  semi-fluid  or  viscous  consistency. 


GLACIER  OF  THE  ALPS. 

These  ice-streams  move  more  or  less  rapidly  according  to 
the  temperature  and  moisture, — the  maximum  rate  being 
thirty  inches  a-day  in  summer,  and  sixteen  in  winter; 
and,  like  rivers,  the  velocity  is  greatest  at  the  centre. 
The  glacier,  in  its  progress  over  abrupt  rocks,  often  splits, 
forming  cracks  or  clefts  of  great  depth,  termed  Crevasses. 
It  soon  becomes  laden  with  loose  stones  and  other  debris, 
termed  Moraines,  collected  from  the  sides  of  the  moun- 


ICE-PACKS.  109 

tains;  and  tliese  are  at  last  deposited,  as  tlie  glacier  melt3 
away,  at  its  lower  extremity.  The  mass,  from  its  immense 
pressure,  grooves  and  grinds  smootli  the  sides  of  the 
mountain  gorges  it  triuersos.  Glaciers  are  most  abun- 
dant in  the  Alps  and  Himalayas,  Norway,  and  New 
Zealand,  as  well  as  in  Polar  regions  generally;  but  they 
occur  wherever  snowy  mountains  of  suificient  height 
exist.  The  snows  and  glaciei^  of  the  Alps  are  estimated 
to  occupy  1400  square  miles,  the  glaciers  numbering  400. 
Mont  Blanc  alone  has  34  glaciers,  covering  95  square 
miles,  its  largest  being  the  Mer  de  Glace  {"  sea  of  ice  ") 
in  the  Valley  of  Chamouni. 

(3)  Icebergs  ("ice-mountains")  are  gi-eat  masses  of 
the  polar  ice-tields  or  glaciers  which  have  protnided  them- 
selves into  the  sea,  and  been  broken  off  and  floated  away. 
The  smaller  masses  are  Ice-floes  ("  ice-islands"),  drifting 
on  the  surface.  These  bergs  are  from  40  to  more  than 
250  feet  above  the  siuface;  but  the  depth  below  is  at 
least  eight  times  greater,  and  they  are  often  several  miles 
in  cii'cumference.  "  They  present  the  appearance  of 
dazzling  white  chalk  clifls  of  the  most  fantastic  shapes," 
and  are  always  grand  and  awful.  Laden  ^\-ith  stones  and 
debris,  they  are  transported  by  winds  and  currents  into 
warmer  latitudes,  where  they  melt  away, — bergs  from  the 
Ai'ctic  Ocean  beins:  met  with  in  the  Atlantic  as  far  south 
as  the  44th  parallel,  and  from  the  Antarctic  Ocean  as  fi\r 
north  as  the  Cape  of  Good  Hope.  They  spread  a  sensible 
degi-ee  of  cold  around  them,  accompanied  "with  fogs,  and 
are  very  dangerous  to  navigation. 

(4)  Ice-packs. — The  Polar  seas  are  frozen  during  the 
gi'eatcr  portion  of  the  year;  and  the  vast  ice-fields, 
when  broken  up  under  the  influences  of  the  advancing 
season,  are  heaped  upon  each  other  and  piled  into  ice- 
packs, which  are  drifted  into  warmer  temperatures. 
Vessels  have  been  frozen  up  and  abandoned,  and  after- 
wards drifted  1000  miles  in  the  middle  of  an  ice-field 
300,000  square  miles  in  extent  and  7  feet  thick;  and 
a  daring  navigator  in  the  Antarctic  Ocean  (Sir  Janu:s 


110  niYSICAL   GEOGRAPHY. 

Boss)  had  to  force  liis  way  1000  miles  throiTgh  sucli 
obstructions. 

63.  Hail. — Hail  consists  of  opaque  frozen  drops  of 
water,  but  sometimes  it  is  a  nucleus  of  snow  coated  with 
ice.  It  is  supposed  to  be  formed  in  the  higher  region  of 
the  atmosphere,  and  to  be  connected  in  origin  with  some 
electrical  disturbance  of  the  air,  for  it  falls  often  during 
thunderstorms.  Hail-stones  are  usually  pear-shaped, 
and  small,  hut  they  have  been  known  as  large  as 
hens'  eggs,  and  even  almost  as  large  as  bricks  when  frozen 
together  in  the  atmosphere.  They  prove  destructive  to 
crops,  and  even  to  buildings  and  animals,  when  of  more 
tlian  ordinary  severity.  Hail  is  most  common  in  summer, 
and  at  or  near  the  hottest  part  of  the  day;  it  occurs  in 
all  latitudes,  but  most  frequently  near  mountains;  it  is 
rare  in  lowland  plains  within  the  tropics,  but  common  at 
several  thousand  feet  of  elevation. 

Influence  of  Climate  on  Health. — "  In  Tropical  coun- 
tries, the  low  grounds  are  covered  with  water  during  the 
rainy  season,  hence  the  unhealthy  vapours  so  fatal  to 
Europeans.  In  the  West  Indies,  the  unhealthy  season 
advances  with  the  sun;  and  along  the  coasts  of  the  Medi- 
terranean, the  mortality  is  doubled  during  the  hot  season 
from  July  to  October.  In  Temperate  regions,  again,  as 
in  the  British  Isles  and  the  greater  part  of  Europe,  deaths 
are  most  numerous  towards  the  end  of  winter,  and  least 
numerous  in  the  middle  of  summer;  because  in  these 
regions  cold  begins  to  be  the  great  enemy  of  the  human 
constitution.  Certain  forms  of  disease  have  a  range 
nearly  corresponding  with  the  several  zones.  Thus, 
malarial  fevers,  especially  that  called  the  yellow  fever, 
are  characteristic  of  the  Torrid  Zone;  typhoid  fevers  and 
consumption,  of  the  Temperate;  colds  and  catarrhs,  of 
the  Frigid,  The  first  class  extends  northwards  in  the 
Atlantic  to  the  Bermuda  Islands,  but  theii'  chief  seats  are 
in  the  Gulf  of  Mexico  and  Guinea;  the  last  prevail  in  all 
places  north  of  the  60th  parallel;  the  second  are  the 
climatic  diseases  of  the  British  Isles." — Clyde's  Geogra2')hy. 


EXERCISES. 


Ill 


1. 

o 
^> 

3. 

4. 

5. 
C. 
7. 
8. 


SujDunY  OF  Causes 

Latitude. 

Altitude. 

Proximity  to  the  Sea. 

Distribution  of  Land  r.ud 
Water. 

Mountain  Chains. 

The  prevailing  AVinds. 

Oceanic  Currents. 

General  Inclination  or  Slope 
of  a  District : — North  Slope 
coldj  South  Slope  warm. 


Affectixq  Climate. 

9.  The  Surface  of  the  Land: 
— Sand  and  Hock  causing 
heat  and  drought;  Vege- 
tation, coolness  and  moist- 
ure. 
10.  Cultivation  of  the  Soil : — 
Tillage  giving  warmth  ; 
Drainage,  dryness;  riant- 
ing,  shelter  and  moisture. 


EXEECISE3. 


1.  Verify  the  estimate  given  in  the  text  of  the  weight  of  air  on 
the  surface  of  the  globe.  Explain  in  your  own  words  the  forma- 
tion of  winds.  State  the  points  of  similarity  between  wands  and 
ocean  currents.  "Which  ocean  currents  are  supposed  to  be  caused 
by  winds,  and  by  which  winds  ?  Which  season  should  be  the 
most  favourable  for  a  voyage  from  China  to  the  Eed  Sea  ?  and 
wliich  for  the  return  voj'age  ?  Which  winds  would  a  vessel  be 
most  likely  to  meet  with  on  a  voj'age  from  London  to  Canton, 
and  from  Xew  York  to  San-Francisco  i  Which  of  them  would  aid, 
and  which  impede  its  progress  ?  Which  winds  are  cold  ?  which 
warm  ?  -which  humid  ?  and  which  dry  ?  Account  for  the  differ- 
ence. Which  cold  winds  are  opposed  to  hot  ones  ?  Which  winds 
prevail  most  during  spring  in  Britain  ?  Are  they  cold  or  warm  ? 
and  why  ?  Write  out  in  your  o^vai  words  a  descriptive  account  of 
the  winds.     Draw  a  map  of  the  Winds. 

2.  Why  is  it  colder  at  the  top  than  at  the  bottom  of  a  mountain? 
Where  in  the  Southern  Hemisphere  does  a  sudden  fall  of  the 
snow-line  occur?  Contrast  the  snow-line  of  the  Pyrenees  and 
Caucasus,  the  Eocky  Mountains  and  the  Cordilleras  of  Chili  with 
each  other.  Compare  the  latitude  and  snow-line  of  England  and 
South  Georgia.  Give  an  instance  of  the  snow-line  being  higher 
on  the  east  than  on  the  west  side  of  a  continent.  Why  should 
the  snow-line  be  higher  in  the  interior  of  contments  than  near 
the  coast?  On  which  side  of  the  Alps  and  Scandinavian  Moun- 
tains should  j'ou  expect  the  snow-line  to  be  highest?  and  why? 
Arrange  in  form  of  a  diaga-am  tJie  heiglit  of  the  snow-line  at 
ditierent  latitudes  from  i)ole  to  pole.  Give  examples  of  countries 
v.ith  insular  climate,  and  of  others  with  continental  climate. 


112  niYSICAL   GEOGRAPHY. 

* 

Wlietlier  should  Edinburgh  or  Moscow,  both  in  the  Scame  latitude, 
be  the  colder?  and  why?  Describe  the  course  of  the  snow-limit. 
Which  continent  is  entirely  beyond  it?  Which  countries  have 
no  snowfall  at  the  sea-level?  What  is  the  diflerence  of  lati- 
tude between  the  north  of  Ireland  and  Portugal,  and  between 
the  Black  Sea  and  Great  Britain?  Which  currents  and  winds 
aflfect  the  temperature  of  the  eastern  and  western  coasts  of  the 
continents  ? 

3.  What  are  the  chief  agents  in  the  production  of  rain?  Ex- 
plain their  action.  Name  mountains  besides  the  Scandinavian 
Alps  which  intercept  the  moisture  of  the  prevailing  winds. 
Account,  if  you  can,  for  the  copious  nightly  dews  of  India  and 
other  tropical  countries.  At  what  periods  are  the  wet  and  dry 
seasons  on  the  east  coast  of  India?  and  when  on  the  west? 
Name  the  European  countries  of  winter  rains,  of  autumn  rains, 
and  of  summer  rains.  Explain  how  the  phenomenon  of  skimming 
fresh  water  from  the  surface  of  the  sea  is  possible.  Which  of 
the  rainless  regions  are  plateaux,  and  which  are  not  ?  How  do 
these  regions  differ  in  direction  in  the  Old  World  and  the  New? 
How  do  they  correspond  in  position?  Illustrate  by  a  scale,  or 
otherwise,  the  gradual  decrease  of  rain  from  the  coast  into  the 
interior.  Which  two  large  rivers  have  their  sources  in  the 
glaciers  of  the  Alps  ?  Which  currents  transport  icebergs?  Which 
thaw  them?  How  much  farther  do  icebergs  travel  from  the 
Antarctic  Ocean  than  from  the  Arctic?  Illustrate  the  effects  of 
each  of  the  ten  leading  Causes  affecting  Climate,  giving  examples 
of  each.  Write  out  a  descriptive  account  of  llains.  Draw  a 
map  of  the  Distribution  of  Eain. 


CHAPTER  YIt 

STEUCTURE  OF  THE  EAETH. 

The  Crust  of  the  Earth — Arrangement  and  Classification  of  Rocks 
— Geographical  Distribution  of  Minerals — Central  Heat — Vol- 
canoes— Volcanic  Phenomena — Distribution  of  Volcanoes — 
Classification  of  Volcanoes  —  Effects  of  Volcanoes  —  The 
Geysers  —  Earthquakes  —  Earthquake  Districts  —  Uses  of 
Volcanic  Agency — Coral  Formations. 

64.  The  Crust  of  the  Earth.— It  is  but  a  very  little 
way  that  man  has  been  able  to  penetrate  into  the  deptlis 
01  the  earth.     The  miner  has  never  reached  farther  than 


CRUST   OF   THE   EARTH.  113 

2000  feet  below  the  sea-level,  or  about  the  Yio.ooo  part  of 
the  semi-diameter,  or  distance  to  the  centre  of  the  globe. 
Lut  by  careful  observation  of  the  arrangement  of  the 
rocks  at  or  near  the  surface,  the  geologist  has  been  able 
to  form  a  tole^-ably  correct  estimate  of  the  composition  of 
the  earth  to  the  depth  of  about  ten  miles. 

All  the  materials  of  the  earth's  crust  have  been  the 
product  of  either  fire  or  water,  and  are  lience  divided  into 
two  great  classes,  Igneous  rocks  and  Aqueous  rocks.  The 
former,  such  as  granite,  basalt,  and  lava,  consist  of  vast, 
iiTCgular  masses,  and  are  therefore  termed  Unstratified  ; 
the  latter,  such  as  sandstone,  limestone,  and  clay,  are 
arran£red  in  reiinilar  lavers  or  strata,  and  are  therefore 
called  Stratified.  Igneous  rocks  have  been  upheaved 
with  tremendous  violence  by  the  elastic  force  of  internal 
heat,  breaking  through  the  overlying  strata,  and  are 
hence  termed  Eruptive  ;  ac|ueous  rocks,  deposited  from 
water,  like  the  mud  and  sands  at  the  bottom  of  our  seas 
and  lakes,  and  afterwards  solidified  by  enormous  pressure, 
are  termed  Sedimentary.  A  thii-d  kind  of  rock,  such  as 
gneiss  and  mica  slate,  called  Metamorphic,  is  of  aqueous 
origin,  and  therefore  stratified  ;  and  their  resemblance  to 
igneous  formations  is  due  to  the  crystallization  caused  by 
subterranean  fires. 

The  igneous  rocks  are  the  oldest,  and  at  the  gi-eatest 
depth,  and  are  entii-ely  destitute  of  animal  or  vegetable 
remains;  the  aqueous  rocks,  the  most  recently  formed, 
and  nearest  the  siuface,  abound  with  organic  remains  in  a 
petrified  state,  and  are  called  Fossiliferous.  Two-thirds 
of  the  surfiice  rocks  of  the  earth  are  fossiliferous;  they 
are  often  thousands  of  feet  in  thickness,  and  theii*  total 
depth  has  been  estimated  at  from  seven  to  eight  miles. 
In  the  chalk  formations  whole  mountains  are  formed  of 
shells  of  microscopic  animals,  so  small  that  it  would  re- 
quire 40,000,000  of  them  to  form  a  cubic  inch.  Tripoli, 
a  powder  for  polishing  metals,  is  largely  composed  of 
them. 

The  stratified  rocks  would  have  occupied  a  position 
23  E  H 


lU 


PHYSICAL  GEOGRAPHY. 


perfectly  liorlzontal,  and  overlying  tlie  otlier  formations, 
had  not  tlie  eruptive  rocks  burst  through  their  strata, 
tilting  them  wp  at  various  angles,  and  taking  a  position 
above  them.  Hence  granite,  which  forms  the  base  of  a 
large  portion  of  the  earth's  crust,  has  been  upheaved  into 
mountain  chains,  and  even  to  the  very  summits  of  the 
Alps.  But  i^erhaps  not  more  than  Yio  of  the  surface  of 
the  dry  land  is  occupied  by  the  unstratified  rocks.  The 
metals  are  of  igneous  origin;  coal  belongs  to  the  aqueous 
formations.  The  different  strata  of  the  earth's  crust  form 
great  and  distinctive  epochs  in  the  history  of  the  forma- 
tion of  the  globe;  and  if  they  are  not  found  invariably 
present  in  all  parts  of  the  world,  they  never  deviate  from 
an  invariable  order  of  succession.  Thus,  coal  is  never 
found  above  the  New  Ked  Sandstone,  or  below  the  Old, 
although  strata  intermediate  in  one  place  may  be  absent 
in  others. 


SECTION   OF  THE  EAKTH  S  CnUST. 

The  actual  state  of  the  earth's  crust  will  be  best  understood 
by  a  reference  to  the  accompanying  ilhistration.  At  a  the  igne- 
ous rocks  are  on  the  surface.  The  earliest  or  lowest  strata  begin 
to  appear  at  h,  and  the  edges  of  others  are  passed  over  in  succes- 
sion as  we  proceed  towards  c.  The  same  strata  occur,  with  a 
still  greater  slope,  between  fj  and  h  ;  but  here  they  are  covered 
by  later  formations  (/,  k),  whose  horizontal  position  shows  that 
they  must  have  been  deposited  after  the  forces  by  which  the 
surrounding  rocks  were  upheaved  had  ceased  to  ox^erate.  The 
eminences  at  c  are  formed  of  volcanic  matter,  ejected  through 
the  opening  seen  at  e ;  and  the  dark  lines  between  h  and  d  repre- 
sent fissures  in  the  various  rocks,  produced  by  earthquakes  and 
similar  convulsions,  and  then  filled  up,  from  subterranean  treas- 
ures, with  metallic  ores  and  other  substances  in  a  state  of  fusion. 
It  is  from  such  fissures,  usually  called  veins,  that  most  of  the 
metals  and  their  ores  are  obtained. 


DISTRIDUTION   OF   MINERALS. 


115 


CLASSlhCATION  AND   ARRANGEMENT  OF  BoCKS. 


SYSTEM3. 


Characteristic  Rocks. 


Perious. 


1.  Post-Tertiary, 

2.  Tertiary,    .    . 

3.  Cretaceous,    "> 

or  Chalk,    J 

4.  Oolitic,  or      ■> 

Jurassic,    } 

5.  Triassic,     ,     . 

6.  Permian, 

7.  Carboniferous, 


8. 

9. 

10. 


Devonian, 

Silurian, 

Metamorpluc, 
or  Crystal 
line  Strata 


^ 


1.  Volcanic,     .< 

2.  Trappcan,    .  ( 
Lie, .    .  < 


3.  Granitic, 


I. — STRATIFIED    ROCKS. 

(Surface  deposits  of  Sands,  Gravels,  Peat- 

[      mosses,  &c., 

Clays,  Sands,  Gravels,  ilails,  <tc.,  .    .     . 

Chalks,  Sandstones,  Clays,  Shales,  .    .    . 

Limestone,  Sandstone,  Clays,  Shales,  .    . 

Upper  New  Red  Sandstone,  Marls,  <tc.,  . 

Lower  New  Red  Sandstone,  Limestone,  &c  , 
fCoal,    Limestone,    Ironstone,    Fire-clay, 

I       Sandstone,  <fcc. 

I  Old  Red  Sandstone ;    .    . 

]  Slates,  Schists,  and  Limestones,      .    .    . 

Gneiss,  Mica-slate,  Schists,  Quartz,  &c.,  ' 
{  (Non-Fossiliferoua;. 

II. — UNSTRATIFIED   ROCKS. 

Lava,  Trachyte  or  Greystone,  Pumice,  Tufa, 

Scorise,  Sulphur,  (tc. 

fzamjjZes.—iEtua,  Vesuvius,  AuvergneMts. 

Basalt,  Greenstone,  Felspar,  Porphjrry,  (fee, 
Examples  .-—The  Ochil  and  Sidlaw  Hills,  . 

Granite,  Syenite,  PorpluTy,  Serpentine, tc, 
Examples  .-—The  Grampian,  Cornish,  aud 
"Wicklow  Mountains, 


")  Cainozoic, 
y  (Ke.ent 
)        Life). 

Jfesozoic 
(Middle  Life) 

or 
Secondary. 

Pala?ozoic 

(Ancient 

Life),  or 

Primary. 

■^  HjTozoic, 
>  (Beneath 
;        Life). 

Associated  with 

Tertiary  and 
upper  secon- 
dary Forma- 
tions. 
{Secondary 
and  Upper 
Primarj-. 
fPrimarj-  and 
I    Metamor- 
l    phic. 


65.  Distribution  of  Minerals. — The  minerals  valuable 
or  useful  to  man  are  very  profusely  distributed  over  the 
eartb,  there  being  few  regions  entii-ely  destitute  of  them, 
and  the  most  useful  are  the  most  plentiful.  But  it  fre- 
quently happens  that  the  vegetable  productions  are  the 
poorest  where  the  mineral  treasures  are  the  richest,  more 
especially  in  the  regions  producing  silver,  lead,  and  coal. 
^Metals  are  generally  found  associated  's\ith  mountains — 
the  metalliferous  strata  having  been  upheaved  along  with 
them,  and  thus  exposed  or  rendered  more  accessible  to 
the  miner. 

Gold  hag  an  especial  preference  for  mountain  chains 
which   nm  north   and   south,  such  as  the  Andes,  the 


116  PHYSICAL   GEOGRAPHY.      . 

Urals,  etc.;  and  it  was  from  this,  along  with,  certain 
geological  analogies,  that  Sir  Roderick  Mui'chison  i>ve- 
dicted  the  presence  of  gold  in  Australia  in  1846,  five 
years  before  its  discovery.  The  New  World  has  been 
always  famous  for  the  richness  and  variety  of  its  mineral 
wealth.  The  riches  of  Peru  and  Mexico  have  been  pro- 
verbial, and  they  formed  the  chief  attractions  to  the 
Spaniards  who  conquered  and  colonized  these  countries. 
The  gold  and  silver  mines  of  both  North  and  South 
America  have  yielded,  according  to  computation,  no  less 
than  1248  millions  of  pounds  sterling  in  the  three  cen-. 
turies  succeeding  theii'  discovery.  California  and  British 
Columbia,  Australia  and  New  Zealand,  are  now  the  chief 
gold-fields  of  the  world. 

Coal  and  Iron,  the  most  useful  of  mineral  products, 
follow  the  same  order  of  distribution,  and  are  very 
widely  diffused;  but  they  have  been  hitherto  most 
worked  in  the  Temperate  Zones,  especially  the  North 
Temperate;  and  the  richest  coal  and  iron  mines  of 
Europe  lie  north  of  the  Alps.  Both  minerals  are 
very  largely  developed  in  Great  Britain,  which  pro- 
duces more  than  100,000,000  tons  annually,  or  more 
than  all  the  rest  of  the  world;  and  they  form  the  chief 
source  of  the  national  wealth.  But  the  lara-est  coal- 
field  in  the  world  is  in  the  United  States  of  North 
America — the  largest  being  in  the  Appalachian  district 
— and  it  is  70  times  the  area  of  the  coal-field  of  Great 
BritaiQ. 

Copper. — To  the  north  and  east  of  Lake  Superior,  in 
North  America,  is  the  richest  copper  region  in  the  world; 
but  that  metal  is  most  extensively  wi'ought  in  England 
and  Chili. 

Rock-salt  is  very  abundant.  Enormous  deposits  of  it 
extend  600  miles  on  each  side  of  the  Carpathians;  and  the 
salt  mines  of  Wieliczka  in  Poland,  are  the  most  famous  in 
the  world,  and  are  wrought  at  a  great  depth.  There  is  a  hill 
of  salt,  500  feet  high,  near  Mont  Serrat  in  Spain;  and  the 
island  of  Ormuz^  in  the  Persian  Giilf^  is  entirely  composed 


DTSTtllDUTlON   OP   CHIEF   MINERAL   PHODUCTS.       lit 

of  it.     The  salt  mines  of  Chesliii-e,  in  England,  supply 
all  the  British  Isles  with  salt. 

The  precious  stones  are  sparingly  distributed.  Brazil, 
celebrated  for  gems  as  well  as  the  precious  metals,  pro- 
duces most  of  the  diamonds  of  commerce;  but  Asia  is  the 
great  storehouse  of  precious  stones — the  finest  and  largest 
diamonds  in  the  world,  fonning  the  cro^vn-jewels  of 
Eiu'ope,  being  from  that  continent. 

GEOGRAPHICAL  DISTRIBUTION  OF  CHIEF  MINERAL 

PRODUCTS. 

GOLD. 
Europe— Transylvania,  Hungary,  North-West  of  Austria,  Ural 

Mountains.  . 

Asia— Ural  and  Altai    Mountains,    Tibet,    China,    Indo-Chma, 

Japan.  . 

Africa— Kong  ISIountains,  East  and  West  Coasts,  South  Africa, 

and  the  interior  generally. 
America— British  Columbia,  California,  Mexico,  Central  America. 
Oceania — Australia,  New  Zealand,  Borneo. 

PLATINUM. 

Europe — The  Urals,  Spain. 
America — New  Granada,  Brazil. 

SILVER. 

Europe— Hungary,  Transylvania,  Bohemia,  Saxony. 

Asia— The  Ural  and  Altai  Mountains,  China. 

America — Mexico,  Peru,  Chili,  and  the  Andes  generally. 

LEAD. 

Europe— Great  Britain,  France,  Spain,  Austria,  Germany. 

Asia — Siberia,  Armenia,  Farther  India,  China. 

America— United    States,    Canada,    California,    Mexico,    Peru, 

Chili,  etc. 
Africa— Algeria  (Atlas  Mountains). 
Australia — South  and  West. 

QUICKSILVER   OR   MERCURY. 

Europe — Austria,  Germany  (Palatinate),  Italy  (Tuscany),  Spain. 

Asia — China,  Japan,  Ceylon. 

America — California,  Mexico,  and  Peru.  ^ 


lis  rUYSICAL   GEOGRAniY. 


COrPER. 


Europe — British  Isles,  Hungary,  Russia,  Norway  and  Sweden,  etc. 

Asia — Siberia,  Persia,  India,  China,  Japan, 

America — Canada  (near  Lake  Superior),  Cuba,  Peru,  Chili,  BraziL 

Africa — Algeria,  Basin  of  Zambesi. 

Oceania — East  Indies,  South  Austraha.  ^ 


TIN. 

Europe — England  (Cornwall),  Saxony,  Bohemia,  France,  Spain. 
Asia — Siberia,  Tenasserim  (Malaya),  Bui'mah,  Assam,  etc. 
America — Mexico,  Peru,  Chili. 
Oceania — Island  of  Banca,  Victoria  in  Australia. 

COAL. 

Europe — Great    Britain,    Belgium,    France,    Russia,    Germany, 

Sweden,  etc. 
Asia — Asia  Minor,  Syria,  Persia,  India,  Burmah,  China,  Japan. 
Africa — Zambesi  Basin,  Natal,  Madagascar. 
America — United  States,  New  Brunswick,  Cape  Breton,  Nova 

Scotia,  Vancouver's  Island,  Cuba,  New  Granada,  Chili,  Brazil. 
Oceania — Australia,  Tasmania,  New  Zealand,  Borneo,  Labuan. 

IRON. 

Europe — The  same  countries  that  contain  coal. 

Asia — Siberia,  Asia  Minor,  Persia,  India,  Japan. 

Africa — Algeria,  Zambesi  Basin,  Cape  Colony,  Natal. 

America — United  States,  Canada,  New  Brunswick,  Nova  Scotia, 

Cape  Breton  Island,  New  Granada,  Bolivia,  Chili,  La  Plata, 

Brazil. 
Oceania — New  South  Wales,  Victoria,  Tasmania,  New  Zealand, 

East  Indies. 

ROCK   SALT. 

Europe — England,  Austrian  Poland,  Russia,  France,  Spain. 
Asia — Armenia,  Syria,  North-West  India,  China,  The  Urals. 
Africa  and  America — Very  generally  diffused. 

PETROLEUM. 

Europe— France,  Italy. 

Asia — Siberia,  Shores  of  the  Caspian,  Persia,  Burmah,  Japan. 
North  America — United  States  (Pennsylvania,  Virginia,  Ohio), 
Canada. 


VOLCANIC   niENOMENA.  119 

66.  Central  Heat. — As  wc  descend  into  tlie  bowels  of 
tliG  cfirth,  the  temperature  is  found  to  increase  -with  the 
df^plh,  in  the  ratio  of  about  one  degree  in  every  51  feet. 
Were  tlic  same  rate  of  increase  to  continue,  at  less  than 
30  miles  from  the  surface  a  degree  of  lieat  would  be 
reached  sufficient  to  melt  every  known  rock.  Hence  it 
is  supposed  that  the  globe  was  originally  a  molten  mass, 
which  has  gradually  cooled  down;  and  that  beyond  that 
depth  (the  supposed  thickness  of  the  earth's  crust)  the 
interior  of  the  eai-th  is  an  immense  seething  cauldrou  of 
fire.  Upon  this  supposition  are  explained  the  phenomena 
of  Volcanoes,  Hot-Springs,  and  Earthquakes.-^ 

Y0LCAX0E3. 

67.  Tolcanocs,  or  Burning  ^Mountains,  emit  from  their 
sides  or  summits  smoke,  ashes,  sulphurous  vapours, 
flames,  and  torrents  of  melted  lava.  Volcanoes  are  not 
necessarily  mountains :  the  volcanic  action  may  originate 
on  level  ground,  either  on  the  land  or  at  the  bottom  of 
the  sea;  but  the  ejected  matter,  gradually  increasing 
around  the  vent,  in  the  course  of  time  forms  a  mountain. 
They  are  generally  of  large  size,  of  a  conical  form,  with 
a  cauldron-like  hollow  at  the  top,  termed  the  crater. 
They  are  either  continuously  active,  intermittent,  or 
extinct.  The  la.st  class  are  those  of  which  histoiT  records 
no  instance  of  activitv,  such  as  the  Auvcrfnie  jMountains 
in  Central  France.  Stromboli  is  an  example  of  the  first 
cla,ss — its  unceasing  fii-es  being  s-tyled  "  the  lighthouse  of 
the  iNIediten'ancan."  But  the  larger  number  have  periods 
of  repose,  amounting  sometimes  to  centuries.  The 
activity  and  frequency  of  eruptions  seem  to  be  gi'eatcr 
when  the  elevation  is  low. 

Volcanic  Phenomena. — In  a  state  of  rest,  volcanoes  at 
all  times  discharge  smoke  and  jets  of  watery  vapour,  but 
on  the  eve  of  an  eruption  the  snows  of  the  summit   (if 

'    *  It  is  proper  to  mention  that  this  theory  of  the  central  heat 
of  the  earth  is  now  disputed  by  some  eminent  writers. 


120 


MlYSiCAL   GEOGRAi'Ii"i% 


above  tlie  snow-line)  melt,  causing  yuddcn  and  destructive 
torrents.  Subterraneous  hollow  sounds  are  heard,  and 
the  earth  vibrates  beneath  the  feet,  sometimes  for  weeks; 
dense  black  smoke  hangs  in  vast  heavy  masses  over  the 
summit.  Then  come  flashes  of  flame,  volleys  of  red-hot 
stones,  discharged  with  reports  like  those  of  a  park  of 
artillery,  and  projected  to  a  height  of  two  or  three 
thousand  feet,  while  showers  of  ashes  and  scorice  (or  dust) 
are  borne  by  the  winds  for  many  miles  around.  The 
climax  is  reached  when  the  lava  (or  melted  minerals)  leaps 
forth  m  living  fountains  of  fire  from  the  summit  and 
heaving  flanks  of  the  mountain. 


CItATER   OF  VESUVIUS   DURING  AN  ERUPTION. 

The  red-hot  stones  are  often  of  great  size  and  weight,  and  have 
been  projected  to  a  distance  of  nine  miles.  From  Vesuvius,  iu 
1779,  the  melted  lava,  mixed  with  scorite  and  stones,  were  thrown 
to  a  height  of  10,000  feet,  or  about  two  miles;  and  on  one  occa- 
sion the  flames  of  Cotopaxi,  in  South  America,  rose  3000  feet 
above  the  edge  of  the  crater,  and  the  noise  was  heard  600  miles 
off.  The  ashes  and  scorise  darken  the  air  for  hours  and  even  days. 
In  an  eruption  of  TomborOj  in  Sumbawa  (East  Indies),  in  1815, 
the  ashes  strewed  the  streets  and  houses  of  Java,  300  miles  off, 
and  were  found  floating  two  feet  thick  on  the  sea  near  Sumatra, 
more  than  1000  miles  distant.     "  The  ashes  and  scorise  were  suflS 


DISTllIBUTIOJ?   OF   VOLCANOES. 


121 


Cient  to  form  three  mountains  equal  to  ;Nront  Blanc,  or  to  cover 
the  whole  of  Germany  two  feet  deep."  In  1845  ashes  from 
Mount  Ilecla,  in  Iceland,  reached  the  Orkney  Islands,  more  tlian 
700  miles  oflF.  It  was  with  ashes  from  Vesuvius,  in  a.d.  70,  that 
the  cities  of  Herculaneum  and  Pompeii  were  destroyed,  being 
lairied  to  the  depth  of  70  to  112  feet. 


VESUVIUS  NOT  IN  A  STATE  OF  ERUrTION. 

The  lava  at  first  is  of  the  consistency  of  honey,  resembling  the 
slag  of  a  furnace,  and  hence  in  general  proceeds  in  majestic  slow- 
winding  streams  of  fire,  varying  in  speed  from  two  miles  an  hour 
to  two^miles  in  ten  years.  Its  heat  is  excessive,  and  it  cools 
slowly;  at  Mount  Jorullo,  in  ]\Iexico,  forty-five  years  after  its 
eruption,  Humboldt  found  a  mass  of  lava  500  feet  thick,  so  hot 
that  "a  cigar  might  be  lighted  at  any  of  the  cracks  a  few  inches 
below  the  surface."  The  amount  of  lava  eje«ted  at  one  eruption 
is  enormous.  "The  most  prodigious  fiery  iiood  on  record  pro- 
ceeded from  Skiiptaa  Yokul,  in  Iceland,  in  1783.  The  lava 
flowed  in  two  nearly  opposite  streams,  50  miles  in  one  direction 
and  40  in  the  other,  with  respective  breadths  of  15  and  7  miles, 
and  an  average  depth  of  100  feet.  The  mass  has  been  calculated 
at  20  billion  cubic  yards,  or  40  billion  tons,  which,  accumulated, 
would  cover  Loudon  with  a  mountain  rivalling  the  Teak  of 
Tenerifi"®." 

68.  Distribution  of  Volcanoes. — Yolcanoc.s  are  not 
confined  to  any  one  region  or  climate  of  tlic  earth,  but  by 
far  the  grcptcr  number  are  found  in  islands  or  mountain 


i22  PHYSICAL   GEOGRAPHY. 

chams  near  tlie  sea-coasb.  Tlio  only  great  exception  to 
this  arrangement  is  the  volcanic  chain  of  Thian-Shan  in 
Central  Asia,  more  than  1500  miles  from  the  sea.  By- 
far  the  greater  number  of  volcanoes,  and  of  the  active 
ones,  no  less  than  about  two-thii\ls  belong  to  the  islands 
and  shores  of  the  Pacific. 

"Along  the  whole  chain  of  the  Andes,  in  Central 
America  and  INIexico,  almost  all  the  loftiest  peaks  are 
volcanic  or  trachytic;  and  the  earthquake  and  eruption 
are  normal,  and  not  exceptional  events.  Along  the 
north-Avest  of  the  American  continent,  the  chain  of  newer 
igneous  formations  is  almost  continuous,  and  in  Oregon 

attains  an  immense  development The  line 

is  continued  along  the  coast  to  the  extreme  west  point  of 
the  continent,  on  the  Aliaskan  peninsula  (which  is  igne- 
ous), and  thence  to  Kamtchatka  by  the  Aleutian  Isles, 
Avhere  eruptions  are  frequent,  and  a  new  island  rose  in 
1814;  thence  again  in  almost  unbroken  succession,  by 
the  Kurile  and  Japanese  islands  (where  outbreaks  are 
frequent,  and  of  excessive  violence),  through  Formosa 
and  the  Philippines  do^vn  to  the  Indian  Archipelago, 
where  Sumatra,  Java,  Sumbawa,  and  Ploris,  exhibit  a 
perfect  rookery  of  volcanoes,  the  scene  of  one  of  the 
most  dreadful  eruptions  of  modern  times  (that  of  Toni- 
boro,  in  1815)."  No  active  volcanoes  appear  in  Australia 
or  Tasmania,  but,  in  a  line  conforming  to  the  curvature 
of  their  coasts,  the  series  is  prolonged  through  Solomon 
Isles,  New  Hebrides  and  Friendly  Isles,  to  New  Zealand, 
and  ''  thence  even  to  the  active  volcanoes  of  IMount 
Erebus,  and  the  extinct  one  of  Mount  Terror  in  South 
Victoria  Land." — Sir  John  HerschelVs Physical  Geogra2')hy. 
Eastern  Africa  is  possessed  of  several  imi)ortant  volcanoes. 
The  principal  seat  of  volcanic  activity  in  Europe  is  in  the 
Llediterranean,  the  whole  of  Italy  and  Sicily,  tlu'ongh  700  miles 
of  length,  being  specially  volcanic.  Of  the  various  vents, 
Vesuvius,  near  the  city  of  Naples,  is  the  only  one  on  the  main- 
land. Etna,  in  Sicily,  nearly  12,000  feet  high,  maintains  such 
a  connection  with  Vesuvius,  that  when  the  one  is  active,  the 
other  is  silent.  Stromboli,  in  one  of  the  Lipari  Islands,  and 
Santorin,  in  the  Grecian  Archipelago,  are  the  other  chief  summits 


CLASSIFICATION  OP  VOLCANOES.  123 

in  this  region.  Mount  Ilccla,  althougli  not  the  liiylicst  and 
largest,  is  the  best  known,  because  the  most  accessible,  of  tho 
seven  volcanic  peaks  of  Iceland.  The  island  of  Jan  jNIaycn, 
to  the  north  of  Iceland,  is  also  volcanic,  and  belongs  to  the 
North  Atlantic  system.  The  island  of  Java  has  the  unhap[)y 
pre-eminence  of  being  the  greatest  scat  of  volcanic  action  ; 
out  of  80  vents  in  the  Sunda  Isles,  no  less  than  43  belong  to 
Java  alone.  A  peculiar  and  awful  interest  attaches  to  a  por- 
tion of  the  tabledand  of  Quito,  which  has  been  supposed  to  be 
merely  the  dome  of  an  enormous  vault  hollowed  out  by  the  action 
of  volcanic  fires.  Forty-live  volcanoes  have  been  counted  be- 
tween the  city  of  Quito  and  the  Pac^iiic  coast.  The  largest  and 
most  terrific  volcano  known  is  Kii'auca,  in  Hawaii,  one  of  tho 
Sandwich  Islands,  in  the  Tacific.  It  presents  the  appearance  of 
a  vast  lake  of  fire,  200  or  300  feet  below  the  surrounding  plain, 
with  more  than  50  craters,  one-half  of  them  belching  forth  smoke 
and  flame,  and  streams  of  lava,  which  "  roar  and  boil  in  endless 
torture." 

The  number  of  active  volcanoes  is  variously  estimated,  but 
Professor  Ansted  gives  the  following  table  of  their  distribution:— 
Position  of  Volcanoes.  Principal  Cones. 

Atlantic  Ocean — Northern  Part,      .         .         .         .10 
,,  Central  Part,         .         .         .         .10 

,,  Southern  Part,      ....       3 

Gulf  of  Mexico— "West  Indian  Islands,  .  .  .10 
Mediterranean — Sea  and  Coasts,  ....  5 
Eed  Sea  and  African  Coast,  adjacent,      ...       2 

Indian  Ocean  (West  side), 3 

Asiatic  Continent,    .......       o 

Asiatic  Coast  and  Islands— Southern  Part,      .         .     75 

J,  Eastern  Part,        .         .110 

Eastern  Archipelago  and  Pacific  Ocean,  .         •     1? 

America — Northern  Series, 4o 

,,         Central  Series, 45 

,,         Southern  Series, 54 

Antarctic  Land, 3 

Total,         ....  3t)G 

69.  Classification  of  Volcauoes.  —  Volcanoes  aro 
divided  into  two  great  classes  of  Central  and  Linear. 

(1)  A  Central  system  consists  of  a  group  of  volcanic 
vents  surrounding  one  principal  cone,  such  as  those  of  tho 
Canary  Islands  with  the  central  Peak  of  Tcnerillb  (Pico  de 
Teyde). 

(2)  A  Linear  system  has  its  series  of  openings  lying 


(Z. 


124  PHYSICAL   GEOGrvAPHT. 

in  the  same  line  of  direction,  and  at  no  great  distance 
apaii},  such  as  the  great  chain  of  the  Andes  and  the 
Asiatic  islands.  The  latter  class  is  the  more  numerous, 
for  out  of  407  active  and  extinct  volcanoes,  only  42  are 
central,  while  365  are  linear;  the  former  consists  of  nine- 
teen groups  or  systems,  the  latter  of  twenty-two. 

70.  Effects  of  Volcanoes. — To  the  energy  of  volcanic 
action  are  attributed  the  elevation  and  subsidence  of  great 
lines  of  coast  in  various  regions  of  the  globe,  and  the 
formation  of  numerous  islands,  and  even  of  entire  con- 
tinents. Indeed,  new  islands  are  still  being  at  intervals 
thrown  up  by  submarine  volcanoes,  some  of  which  dis- 
a2:)pear  again  in  a  few  months,  while  others  remain  firm,  or 
pai'tially  subside  beneath  the  waves,  and  form  dangerous 
shoals.  Hills,  too,  of  considerable  mass  still  rise  within 
a  brief  period :  Mount  Jorullo,  to  the  west  of  the  city  of 
Mexico,  in  1759,  rose  out  of  the  plain,  along  with  several 
square  miles  around  it.  In  the  space  of  two  days  it  was 
raised  1375  feet — its  height  above  the  sea  being  now 
4265  feet. 

As  special  features  of  volcanic  action  may  be  mentioned 
the  solfataras  ("  sulphur  grounds ")  and  fumeroles 
('^  smoke  vents")  of  dormant  or  extinct  volcanoes;  mud- 
volcanoes,  as  in  Sicily,  Java,  and  Trinidad  (in  the  West 
Indies);  the  Fires  of  Baku,  or  "fields  of  fire,"  west  of 
the  Caspian,  the  sacred  region  and  place  of  pilgrimage  to 
the  Guebres,  or  fire-worshippers;  the  Fire-springS  and 
Fire-hills  of  China;  and  the  Geysers,  or  boiling  springs 
of  Iceland.  , 

Geysers. — The  Geysers  {''rocarers")  are  a  group  of  hot  springs 
in  Iceland,  thirty-six  miles  north-west  of  Mount  Hecla,  and 
within  sight  of  it.  They  are  more  than  fifty  in  number,  and  of 
various  sizes — some  tranquil,  others  boiling  regularly  or  at  inter- 
vals, and  all  are  filled  with  water  clear  as  crystal,  and  surrounded 
by  silicious  incrustations  formed  from  the  silica  infused  in  the 
water.  The  two  largest  are,  the  Great  Geyser  and  the  New 
Geyser  or  Strokr  ("  churn"),  about  100  yards  apart.  The  Great 
Geyser  consists  of  a  circular  pool  or  basin,  72  feet  at  its  greatest 
diameter,  and  4  feet  deep,  situated  on  the  summit  of  a  mound  of 
eilicious  deposit,  15  feet  above  the  neighbouring  ground.     In  the 


EARTHQUAKES.  125 

centre  is  a  pit  8  feet  wide  and  83  feet  in  perpendicular  deptli,  np 
which  heated  water  is  constantly  ascending.  Every  few  hourd 
the  water  rises  in  iets  a  few  feet  above  the  surface  with  a  rumb- 
liu'T  noise,  and  acain  subsides ;  but  about  once  a-day  this  tumult 
ends  in  a  terrific  outb.irst,  which  may  last  about  liftecn  minutes, 
when  the  water  is  tlirown  in  jets  to  a  height  of  GO  to  80  feet,  ob- 
scuring the  country  around  with  volumes  of  steam.  The  water 
at  the  edge  of  the  basin  has  a  temperature  of  187"  Fahrenheit, 
but  immediately  before  an  eruption  that  at  the  bottom  of  the 
deep  tube  or  vent  has  been  ascertained  to  be  uo  less  than  2G1', 
or  49'  higher  than  that  of  boiling  water. 

EARTHQUAKES. 

71.  The  volcano  and  the  earthquake  are  intimately 
connected,  and  are  evidently  phases  of  the  same  pheno- 
menon, viz.,  the  high  temperature  of  the  interior  of  the 
earth.  The  latter,  indeed,  is  frequently  the  precursor  or 
concomitant  of  the  former. 

Earthquakes  may  be  defined  as  more  or  less  violent 
commotions  of  the  surface  of  the  earth.  They  are  of 
several  kinds  —  tremulous,  vertical,  horizontal,  and 
rotatory. 

The  tremulous,  common  in  Chili  and  neighbouring 
countries,  are  least  destructive;  the  vertical,  or  perpen- 
dicular, act  like  the  explosion  of  a  mme;  the  horizontal, 
common  to  all  gi'eat  convulsions  of  the  earth,  resemble 
the  undulations  of  the  waves  at  sea,  and  progress  at  a 
speed  of  20  to  30  miles  in  a  minute;  the  rotatory 
are  most  rare,  but  most  destructive.  The  direction 
of  the  concussions  is  either  linear,  like  that  of  Guada- 
loupe  (1842),  which  extended  3000  miles  in  a  right  line, 
and  60  to  70  in  breadth;  or  circular,  like  that  of  Cala- 
bria (1783);  or  elliptical,  like  the  great  earthquake  of 
Lisbon  (1755).  The  area  of  concussion  is  sometiuics 
immeiiBe,  and  the  devastation  fearful. 

The  earthquake  of  Lisbon  was  felt  over  an  area  four  times  the 
size  of  Europe,  or  one-twelfth  of  the  superficial  area  of  the  globe. 
It  shook  the  continent  of  Europe,  and  rocked  the  waters  of  Lake 
Ontario  in  North  America,  and  the  Atlantic  Ocean  was  so  agi- 
tated tUat  many  islands  ia  tho  West  Indies  were  ovcrilowcd,  aaJ 


* 


12G  PHYSICAL  GEOGRAPny. 

the  waves  rose  50  feet  at  Lisbon  above  their  usual  level.  The 
V'hole  city,  with  60,000  souls,  was  destroyed  in  six  minutes.  In 
1812,  the  city  of  Caraccas,  with  12,000  inhabitants,  perished 
under  three  successive  shocks  in  fifty  seconds.  In  the  east  of 
Calabria,  in  an  area  of  22  square  miles,  200  towns  and  villages, 
with  100,000  inhabitants,  were  destroyed.  On  the  13th  of 
Augiist,  1868,  occurred  the  great  earthquake  of  South  America, 
the  most  fearful  and  destructive  that  has  taken  place  within  the 
present  century.  It  was  confined  to  the  west  side  of  the  Andes, 
but  these  mountains  were  shaken  to  the  height  of  13,000  feet. 
It  was  accompanied  by  several  lesser  convulsions  in  California, 
Vancouver's  Island,  New  Zealand,  and  the  British  Isles ;  and  the 
ocean  was  disturbed  over  an  area  of  30  million  square  miles, 
nearly  equal  in  extent  to  that  of  the  Old  World.  Whilst  many 
cities  in  Peru  and  Ecuador  were  destroyed,  no  less  than  from 
20,000  to  30,000  of  the  inhabitants  of  Ecuador  perished. 

These  appalling  devastations  sometimes  happen  without  warn- 
ing, but  generally  they  are  preceded  by  loud  detonations  from 
underground,  which  resemble  the  roll  of  thunder,  the  rattling  of 
heavy  waggons  over  a  stone  pavement,  or  the  irregular  firing  of 
cannon. 

72.  Earthquake  Districts. — The  regions  visited  by 
earthquakes  are  in  general  the  same  as  the  volcanic  dis- 
tricts, but  the  most  violent  convulsions  generally  happen 
remote  from  the  seats  of  active  volcanoes.  The  latter 
serve  as  vents  or  safety-valves  to  allow  the  elastic  forces 
beneath  the  crust  to  escape,  whereas  in  remote  regions 
the  surface  is  convulsed  and  torn  by  the  raging  elements 
struggling  to  get  free.  The  great  earthquake  districts 
are  those  of  the  Mediterranean  Basin,  Central  Asia, 
Iceland,  and  America.  The  first  two  are  connected,  and 
extend  from  the  Azores  to  Lake  Baikal — the  longest  and 
most  regular  zone  of  volcanic  action  in  the  world.  The 
line  of  concussion  is  determined  by  the  direction  of  the 
principal  mountain  chains.  The  American  district  lies 
cliiefly  on  the  west  coast,  along  the  line  of  the  Andes; 
but   it   also   extends   along   the   north   coast   of  South 

America,  and  into  the  West  Indian  Islands.  

•  The  Effects  of  Earthquakes  are,  the  elevation  and  de- 
pression of  great  tracts  of  land,  the  opening  of  great 
fissures,  and  violent  oceanic  movements.  After  the  great 
earthquake  of  1822^  the  coast  of  Chili  was  permanently 


USES  OF  VOLCANIC  AGENCY. 


127 


raised  from  tlirce  to  four  feet  for  a  distance  of  100  miles. 
On  the  other  Land,  wliole  cities  and   mountains   liavo 


been  engulfed  in  the  sea. 


EARTHQUAKE   FISSURES   IN   CALaERIA. 

73.  Uses  of  Volcanic  Agency. — It  is  originally  due  to 
volcanic  agency  that  the  metals  and  the  rocky  strata  so 
useful  to  man  have  been  brought  within  his  reach,  and 
that  the  surface  of  the  earth  is  not  one  uniform  level,  but 
is  diversified  with  mountain  and  valley,  plain  and  plateau. 
But  the  imceasing  influences  of  aqueous  and  atmosi^heric 
agency,  such  as  frost  and  rain,  wind  and  wave,  if  not 
counteracted,  would,  in  the  course  of  ages,  reduce  the 
higher  portions  of  that  surface  to  a  dead  level ;  even  the 
sea  would  usurp  the  place  of  the  land,  and  the  conditions 
of  animal  and  vegetable  life  would  be  seriously  disturbed. 
Such  processes  of  disintegration  and  waste  are  indeed 
constantly,  though  slowly,  taking  place  around  us,  as  they 
have  ever  been  in  the  history  of  the  structure  of  the 
globe;  but  volcanic  forces  are  ever  and  anon  engaged  in 
the  process  of  upheaval  and  reconstruction.     By  the  two 


12S  PHYSICAL   GEOGRAPHY. 

great  antagonistic  principles  of  fire  and  water  tlie  general 
equilibrium  of  the  crust  of  the  earth  is  preserved.  While 
extensive  areas  of  subsidence  occur  in  some  regions,  as 
extensive  areas  of  elevation  occur  in  others:  thus,  the 
west  coast  of  Norway  and  the  northern  shores  of  the 
Baltic  have  been  raised  hundreds  of  feet,  and  are  still 
rising  at  the  rate  of  four  feet  in  a  century;  the  south  of 
Sweden  and  west  of  Greenland,  on  the  other  hand,  are 
slowly  subsiding  beneath  the  waters.  E-aised  sea-beaches 
and  submarine  forests  afford  similar  evidences  of  elevation 
and  depression  in  our  own  island.  Not  altogether,  there- 
fore, by  a  mere  figure  of  speech,  does  the  poet,  in  the 
well-known  lines,  speak  of  the  time — - 

* '  When  Britain  first,  at  Heaven's  command, 
Arose  from  out  the  azure  main." 

CORAL  FORMATIONS. 

74.  Besides  the  volcano  and  the  earthquake,  another 
great  agency  is  at  work,  incessantly,  yet  peacefully,  in 
changing  the  surface  of  the  globe  and  preparing  abodes 
for  man.  Over  extensive  areas  within  the  Tropics,  in  the 
Indian  and  Pacific  Oceans,  particularly  the  latter,  immense 
numbers  of  islands  and  reefs  have  been  formed,  and  are 
still  being  formed,  by  coral  insects.  These  creatures 
are  not  properly  insects,  as  they  are  commonly  called,  but 
polypi.  They  are  of  various  sizes,  shaj^es,  and  colours, 
and  they  abound  in  myriads.  They  cease  to  live  at  a 
greater  depth  than  from  25  to  30  fathoms,  and  from  this 
depth  they  build  up  to  the  surface  perpendicular  walls  of 
coral — the  material  being  carbonate  of  lime,  secreted 
from  the  waters  of  the  ocean,  and  cemented  into  the 
hardest  of  rock. 

"  The  reef,  rising  in  the  form  of  a  gigantic  cauliflower," 
at  length  reaches  the  surface;  fragments  of  rock  are 
thrown  up  by  the  violence  of  the  surf,  and  raised  above 
the  water;  these  arrest  trunks  of  trees  and  other  drift- 
wood, which  collect  into  a  mass.     Vegetation  speediJ,y 


CORAL    FORMATIONS.  129 

appears  upon  soil  and  sand  formed  from  the  pulverized 
rock;  the  cocoa-nut  tree  and  stately  palm  shoot  up,  and, 
descried  in  the  horizon,  attract  sea-fowl  and  other  birds, 
and  last  of  all,  man  himself,  to  the  newly  created  island. 
Sometimes  the  mass  has  been  raised  by  submaiine  forces 
— the  volcano  and  the  earthquake;  but  there  are  also 
extensive  areas  of  subsidence  where  the  coral  formations 
Lave  simk  and  again  been  built  upon. 

Coral  formations  are  of  three  kinds  : — Lagoon-islands  or  atolls, 
barrier-reefs,  and  f ringing-reefs. 

(1)  Lagoon-islands  or  atolls  are  the  most  numerous  class,  and 
consist  of  a  low  belt  of  coral,  about  a  quarter  of  a  mile  broad, 
surrounding  a  lagoon  or  isolated  portion  of  the  ocean,  of  various 
forms  and  dimensions.  **  A  strip  of  land,  a  few  hundred  yards 
wide,  is  covered  with  cocoa-nut  trees,  above  which  is  the  blue 
vault  of  heaven.  This  band  of  verdure  is  boimded  by  a  beach  of 
glittering  white  sand,  the  outer  margin  of  which  is  encircled 
with  a  ring  of  snow-wliite  breakers,  beyond  which  are  the  dark- 
heaving  waters  of  the  ocean.  The  inner  beach  encloses  the  still 
clear  waters  of  the  lagoon,  resting,  in  its  greater  part,  on  white 
sand,  and,  when  illuminated  by  a  vertical  sun,  of  a  most  vivid 
green."  Encircling-reefs  differ  from  these  oidy  in  having  several 
islandswithin  the  enclosure,  such  asOtaheite  in  the  Society  Islands. 
By  openings  or  channels  in  tlie  reefs,  vessels  may  enter  the  in- 
terior expanse,  and  find  excellent  harbourage.  These  openings 
occur  invariably  on  the  leeward  side;  and  that  side  Is  always  on 
lower  ground  than  the  windward. 


LAGOON   ISLAND   OR   ATOLL.  VOLCANIC   ISLAND. 

Atolls  occur  in  three  main  groups — the  Caroline  Archipelago, 
north  of  the  Equator  ;  the  Low  Archipelago,  south  of  the 
Equator ;  and  the  Laccadive,  Maldive,  and  Chagos  groups,  in  the 
Indian  Ocean. 

23  b  I 


130  niYSICAL   GEOGRAPliY. 

(2)  Barrier-reefs  extend  in  a  straight  line  in  front  of  a  continent 
or  large  island,  at  some  distance  from  the  land,  such  as  the  ' '  Great 
Barrier  E,eef"  to  the  north-east  of  Australia,  more  than  1000 
miles  in  length,  from  200  yards  to  one  mile  in  breadth,  and  from 
20  to  70  miles  from  shore.  That  to  the  west  of  New  Caledonia 
is  400  miles  long,  and  from  8  to  16  miles  from  shore.  The  Fejee 
and  Society  Islands  have  also  barrier-reefs. 

(3)  Fringe-reefs  are  small  narrow  belts  of  coral  that  closely  line 
the  shores.  They  abound  among  the  islands  of  the  Indian 
Archipelago  and  South  Pacific,  as  well  as  on  the  shores  of  Mada- 
gascar, Eastern  Africa,  and  the  West  Indies. 

These  three  forms  of  r&ef  are  all  due  to  the  same  cause — the 
gradual  submergence  of  the  land.  First,  the  coral  insects  built 
the  fringe-reef  close  in  shore.  As  the  island  sank,  a  smaller  sur- 
face was  protruded,  so  as  to  leave  more  sjDaoe  between  it  and  the 
reef;  and,  as  the  insects  still  built  upwards,  it  became  a  harrier- 
reef.  Lastly,  the  island  disappeared  beneath  the  waters,  leaving 
the  lagoon  inside  the  aioll.  The  atoll  thus  resulted  from  the 
barrier-reef,  and  the  barrier  reef  from  the  fringing- reef.  Such  is 
Mr.  Dar^^iu's  theory. 


EXERCISES. 

1.  Write  out  in  your  own  words  an  account  of  the  two  great 
classes  of  rocks.  Give  the  ten  systems  of  rocks  in  descending 
order,  and  divide  them  into  periods  or  epochs.  Name  mountain 
ranges  containing  gold  besides  those  mentioned  in  the  text. 
Which  mountains  are  the  richest  in  metals?  What  tAvo  minerals 
are  in  general  found  in  close  connection?  and  what  is  the  advan- 
tage of  this  arrangement  ?  Which  are  the  useful,  and  which  the 
precious  metals?  Whnt  two  great  agencies  are  employed  in 
operating  upon  tlie  crust  of  the  earth?  If  heat  increases  in 
descending  towards  the  centre  of  the  earth  at  1°  for  every  54  feet, 
at  what  depth  would  we  reach  the  boiling  point  of  water  {212°r.), 
and  of  iron  (2800'' F.)?  What  proportions  do  these  depths  bear 
to  the  diameter  of  the  earth  ? 

2.  Describe  in  your  own  words  the  phenomena  attending  a 
volcanic  eruption.  Group  the  volcanoes  of  the  globe  according 
to  ocean  basins.  Which  volcanic  systems  are  at  the  entrances 
of  the  Arctic  Ocean?  Which  is  the  most  northerly?  Which  the 
most  southerly?  Trace  on  the  map  those  along  the  Pacific  sea- 
board. Where  are  volcanoes  farthest  inland?  Which  continent 
has  most  ?  ^^^lich  fewest  ?  What  part  of  the  mainland  of  Asia 
iiaa  most  t    Nam©  those  of  Europe — what  class  do  they  belong 


DISTRIBUTION    OF    PLANTS.  131 

to?  and  how  aro  they  situated?  Name  the  principal  volcanic 
island-chains.  Name  solitary  volcanic  islands.  Give  some  of 
the  principal  volcanic  peaks.  What  mountains  bound  the  earth- 
quake district  of  the  Mediterranean?  Name  a  few  of  the  great- 
est earthquakes,  with  their  dates.  Draw  a  chart  showing  the 
distribution  of  volcanoes  and  eartlu^uakcs.  Describe  in  your 
own  words  coralline  formations.  Namo  the  prmcipal  coralline 
groups  in  the  Pacilic. 


CHAPTER  YII. 
\^      DISTKIBUTION  OF  TLANTS. 

General  Characteristics  of  Plants — General  Distribution — Zones 
of  Vegetation — Ascending  Zones  of  Vegetation — Botanic 
Eegions  —  Agricultural  Zones  —  Chief  Vegetable  Products 
and  the  Countries  of  their  Production. 

75.  General  Characteristics  of  Plants. — Vegetation 
is  universally  diliused  over  the  globe,  extending  even  to  tlie 
regions  of  perpetual  snows  and  the  extreme  depths  of  the 
ocean.  For  even  on  the  snows  of  the  Arctic  Zone,  and 
of  the  higher  Alps  and  Pyrenees,  may  be  seen  the  pal- 
mella  nivalis,  or  red  snow,  which  is  a  minute  species  of 
plant.  Light,  heat,  and  moisture  are  the  principal  con- 
ditions conducing  to  the  growth  of  plants;  but  the  entii'e 
absence  of  moisture  alone  proves  fatal.  The  total  num- 
ber of  species  of  plants  has  been  estimated  at  120,000. 
These  are  divided  into  two  great  classes,  viz.: 

I. — Cryptog'amous,  ov  Jlowerless  plants;  as  mosses, 
lichens,  fungi,  ferns,  and  sea-weed; 

II. — Phanerogamous,  or  Jlowering  plants,  which  con- 
sist of — 

(1)  Endogenous  plants,  whose  stems  increase  from 
within;  as  the  numerous  grasses,  lilies,  and  palms;  and, 

(2)  Exogenous  plants,  whose  stems  increase  from  'with- 
out; such  as  the  forest  trees  (deciduous)  and  most  flower- 
ing plants  and  shrubs.     The  lii\st  class  form  only  ^/g  of 


132  PHYSICAL   GEOGRArilY. 

the  whole,  and,  with  the  important  exception  of  ferns, 
are  most  abundant  in  Polar  and  Alpine  regions,  but  de- 
crease towards  the  Equator.  On  the  other  hand,  exogens 
in  Tropical  regions  are  to  the  endogens  as  four  to  one;  in 
the  Temperate  as  six  to  one;  and  in  the  Arctic  not  more 
than  two  to  one. 

76.  General  Distribution. — The  elements  of  light,  heat, 
and  moisture,  being  in  greatest  intensity  within  the 
Tropics,  there  we  find  the  greatest  development  of  vege- 
table life;  and  a  gradual  declension  takes  place  as  we 
proceed  towards  either  Pole. 

Intertropical  vegetation  is  the  most  varied  and  luxu- 
riant, and  of  the  noblest  kinds;  the  trees  are  lofty  and 
huge,  with  large,  bright,  evergreen  leaves,  and  splendid 
flowers,  and  are  matted  over  with  gigantic  climbers  and 
parasites,  so  dense  as  to  make  the  forest  impenetrable. 
Aromatic  shrubs  abound,  while  reeds  rise  to  the  height 
of  100  feet,  and  rigid  grasses  to  40.  To  this  region 
belong  the  palm,  the  loftiest  of  trees;  the  baobab,  the 
thickest;  and  the  banyan,  the  shadiest. 

In  the  Temperate  Pegions  more  hardy  forms  and 
families  appear:  the  large  towering 'Evergreen  trees  give 
place  to  deciduous  trees  (oak,  ash,  elm,  etc.);  the  tall 
rigid  grasses  of  the  dense  jungle  to  vivid  green  meadows, 
with  tender  herbs;  and  the  vine  and  cereal  grasses  are 
cultivated  and  brought  to  perfection.  Then  succeed  dark 
forests  of  fir  and  pine  at  the  sea-level  towards  the  north 
of  Europe,  Asia,  and  America,  but  at  from  10,000  to 
12,000  feet  of  elevation  within  the  Tropics.  These,  in 
their  turn,  gradually  disappear  with  increase  of  latitude. 

The  trees  are  dwarfed  by  the  cold  into  mere  shrubs, 
such  as  the  dwarf  willow,  birch,  and  alder.  Although 
the  rhododendron  is  the  characteristic  plant  of  the 
Arctic  Zone,  it  is  found  abundantly  only  on  high 
elevations,  such  as  the  Himalayas  and  the  Alps.  The 
degeneration  of  vegetable  life  continues  till  lichens  and 
mosses,  its  lowest  forms^  are  reached  in  the  Pegions  of 
THE  Poles. 


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tOTANIC   REGIONS. 


133 


Zones  of  YrGETAXioy. 


Zones. 

Characteristic  Plants. 

Zones. 

Characteristic  Plants. 

E'iuatorial,    .     . 
Tropical,  .     .     . 
Sub-Tropical,     . 
AVarmTcmperate, 
Cold  Temperate, 
Sub-Arctic,   .     . 

Palms  &,  Bananas. 
Tree  Ferns  &  Figs. 
Myrtles  &  Laurels. 
Evergreen  Trees. 
Deciduous  Trees. 
Pines  (Coniferre). 

Arctic, 
Polar, 

Rhododendrons, 
with  Dwarf  Wil- 
low, Birch,  and 
Alder. 

Alpine  Plants. 

It  is  only  in  a  general  sense  that  these  zones  are  limited  by 
parallels  of  latitude ;  they  are  bounded  rather  by  lines  of  equal 
mean  summer  temperature,  so  that,  strictly  represented,  their 
limits  would  present  undulating  lines.  But  they  are  necessarily 
ill-defined,  as  they  often  overlap  or  run  into  each  other,  from  a 
greater  or  less  number  of  species  being  common  to  two  conter- 
minous zones. 

\  Ascending  Zones  of  Vegetation. — Temperature  de- 
creases with  altitude  about  1'  for  every  350  feet.  In 
ascending  a  lofty  mountain  near  the  Equator,  the  travel- 
ler passes  through  successive  zones  of  vegetation  analo- 
gous to  those  between  the  Equator  and  the  Poles.  "A 
few  hundred  feet  more  or  less  of  elevation  is  sufficient  to 
change  the  whole  physical  aspects  of  a  country, — con- 
verting arable  lands  and  vineyards  into  pasture  lands, 
pasture  lands  into  pine  forests,  and  pine  forests  into 
regions  of  everlasting  snow  and  glaciers."  *•  We  may 
begin  the  ascent  of  the  Alps,  for  instance,  in  the  midst 
of  warm  vineyards,  and  pass  through  a  succession  of 
oaks,  sweet  chestnuts,  and  beeches,  till  we  gain  the 
elevation  of  the  more  hardy  pines  and  stunted  birches, 
and  tread  on  pastures  fringed  by  borders  of  perpetual 


snow 


.. " 


Botanic  Regions. — Independently  of  climate,  certain 
forms  of  vegetation  are  restricted  to  certain  areas,  or  are 
predominant  within  them.  Hence  botanists  sub-divide 
the  earth  into  twenty-five  botanic  regions,  such  as  the 
region  of  mosses  and  saxifrages  lying  within  the  Arctic 
Circle;    the  region  of   the    tea  -  plant  and   camellia  in 


131 


niYSICAL  GEOGRAPHY. 


Ecastern  Asia;  tlie  region  of  palms  in  South  America, 
east  of  the  Andes  and  between  the  Equator  and  the 
Tropic  of  Capricorn,  eto.  America  excels  every  other 
quarter  of  the  globe,  not  only  for  the  luxuriance  and 
splendour,  but  for  the  variety  of  its  flora.  It  has  more 
than  double  the  number  that  are  natives  of  Europe;  Asia 
has  fewer  than  Europe;  Oceania  fewer  than  Asia;  and 
Africa  the  least.  Great  mountain  chains  separate  botanic 
regions  as  effectually  as  the  ocean;  and  the  same  families 
do  not  occur  in  regions  far  apart  in  which  the  climatic  and 

Perpetual  Snow./ j<  V\\ 
Licnens.  ^^jl^^^^ 

PeruTian  Bark  TrSfcS  fClnchonaeJ  /l-l^\^J^%^t^^^  i. 

Ordinary  Forest  Trees.  ^-^l^W^'^'^J^t'-i'^^^^^ 

Tree  rerns.^^-c:^.t^x-|£?-'t3^;Vr'^CS5^ 

Sea  Lcvoi  aC  tlie  Equator. 

VERTICAL  DISTEIEUTION  OF  PLANTS. 

other  conditions  appear  the  same,  but  similar  or  reiwe- 
sentative  species  occur.  The  heaths  of  EurojDe  have  re- 
presentatives, more  rich  and  numerous,  in  South  Africa ; 
but  heaths  are  entirely  absent  in  America.  The  Cactus 
plants  of  South  America  are  represented  by  the  Eupliorhice 
of  South  Africa.  On  the  other  hand  the  rose,  Avith  the 
common  fruits  and  food-plants  of  Europe,  are  unknown 
in  the  Southern  Hemisphere.  Australia  possesses  the 
most  singular  vegetation  known :  "  persistent-leaved  trees, 
Avith  hard  narrow  leaves  of  a  sombre  melancholy  hue, 
and  whole  shadowless  forests  of  leafless  trees."  Such 
are  the  gum-trees  and  leafless  acacias. 


aghicultuhal  zones. 


135 


77.  Agricultural  Zones. — Tlic  cullivatod  food-pro- 
dvicing  plants  are  arranged  in  the  following  order,  from 
tlie  Tropics  nortlnvards : — - 

(1)  Zone  of  rice,  millet,  and  maize; 

(2)  Zone  of  maize  and  wheat; 

(3)  Zone  of  wheat,  rye,  buckwheat,  pease,  and  beans ; 
(■i)  Zone  of  barley,  oats,  bere,  and  the  potato. 

Rice  has  its  i^ivonrite  seat  in  South-Eastem  Asia,  and, 
along  witli  pulse,  feeds  more  human  beings  than  any 
other  gi-ain;  millet  (also  called  Durra)  is  grown  exten- 
sively in  the  countries  around  the  Red  Sea;  and  maize 
is  most  widely  dififused  in  America — extending  from  CliilL 
to  Canada.  The  common  grains  of  Europe,  Avheat,  rye, 
etc.,  are  supposed  to  have  been  transferred  from  the  North 


EIIEAD   FEU  IT. 


of  Persia  and  India,  and  the  cereals  generally  are  the  most 
easily  transferred  of  vegetable  products.  The  potato,  the 
most  widely  distributed  of  food-yielding  plant?),  is  a  native 


136  FHYSIGAL   GEOGRAPHY. 

of  Chili  and  Peru;  it  is  grown  everyAvliere  except  in  inter- 
tropical lowlands,  "where  it  is  replaced  hj  the  batata,  or  sweet 
potato,  in  the  New  World,  and  by  the  yam  in  the  East  and 
West  Indies.  Tobacco,  also  from  America,  is  the  most 
widely  distributed  luxury;  it  gi'ows  everywhere  within  the 
Tropics,  and  also  beyond  them,  but  not  so  far  north  as  the 
potato.  The  tea-plant  has  its  favourite  seat  on  the  hilly 
grounds  of  Southern  China,  beneath  the  Troj)ic  of  Cancer; 
the  coffee-plant,  a  native  of  Kaffa  in  Eastern  Africa,  is 
produced  most  largely  in  Arabia,  Ceylon,  Java,  and 
Brazil;  and  the  vine  is  of  the  Warm  Temperate  Zone. 
Food-yielding  trees  within  the  Tropics  are  the  palm,  the 
j)lantain  or  banana,  the  baobab,  the  manioc,  and  bread- 
fruit tree;  and  to  the  same  region  belong  most  of  our 
spices  and  the  sugar-cane.  Of  clothing  j^lants,  cotton, 
the  most  extensivelv  used  material  of  clothincf,  flourishes 
on  both  sides  of  the  Tropics,  and  in  both  the  Old  World 
and  the  New;  while  hemp  and  flax  are  the  only  cloth- 
ing plants  of  the  Temperate  Zone. 

VEGETABLE  PEODUCTS  AND  THE  CHIEF  COUNTPJES 
OF  THEIR  PEODUCTION. 

Almonds — France,  Spain,  Italy,  the  Levant. 

AI08S — Bombay,  Arabia,  Socotra,  Cape  Colony,  the  Levant,  West 
Indies. 

Arrow-root — East  and  West  Indies,  Bermudas,  South  America, 
Africa. 

Banana  or  Plantain — All  tropical  and  sub-tropical  countries. 

Batata  or  Sweet  Potato — All  tropical  and  sub-tropical  countries. 

Barley — Chiefly  Belgium,  Holland,  Prussia,  Denmark,  Britain; 
but  generally  from  45°  to  69|°  N.  latitude  in  the  Eastern 
Hemisphere. 

Bread-fruit — South  Sea  Islands  and  East  Indies. 

Cacao  or  Cocoa — All  tropical  and  sub-tropical  countries. 

Cocoa-nuts — All  tropical  and  sub-tropical  countries. 

Camphor — China,  Japan,  Cocliin-China,  Java,  West  Indies. 

Caoutchouc  or  India-rubtoer— East  Indies,  Guiana,  Brazil,  West 
Indies, 

Capers — South  of  France,  Italy,  Sicily,  and  Mediterranean  coun- 
tries. 

Chestnut — Asia  Minor,  Sardinia,  and  soutli  of  Europe. 


VEGETABLE  PRODUCTg.  137 

Chicory — En£;lan(l  and  continent  of  Europe. 

Cinnamon — Ceylon  and  West  Indies. 

Cloves — East  Indies  (Moluccas),  Bourbon,  ^lauritius,  West  Indies. 

Coffee — Arabia,    West    Indies,    Brazil,    East    Indies,    Bourbon, 

Guiana. 
Cork — Soutli  of  Europe  (chiefly  Spain  and  Portugal),  and  north 

of  Africa. 
Cotton — All  countries  within  35°  N.  and  35°  S.  lat.,  especiallj 

United  States,  West  Indies,  Brazil,  Egj'pt,  East  Indies. 
Currants — Greece,  including  the  Ionian  Islands. 
Dates — North  of  Africa,  Arabia,  Persia,  India,    . 
Ebony — India,  Ceylon,  Mauritius,  Madagascar. 
Esparto — South  of  Europe,  especially  Spain. 
Figs — ^Tropical  and  sub-tropical  countries,  especially  around  tho 

^Icditerranean. 
Flax  or  Lint  and  Hemp — The  temperate  parts  of  Asia  and  North 

America,    Egypt,    Belgium,    Pussia,    south    shores    of    the 

Baltic,  and  Ireland. 
Ginger — East  Indies,  West  Indies,  Sierra  Leone. 
Indigo— India,  Egj'pt,  West  Indies,  Mexico,  Central  America, 

Brazil. 
Jute — India. 

Lemon — Countries  on  the  Mediterranean,  Portugal,  India,  Brazil. 
Logwood — Mexico,  Central  America,  West  Indies. 
Madder — Holland,  Italy,  Turkey,  India,  China. 
Mahogany — West  Indies,  Honduras,  South  America. 
Maize  or  Indian  Com — America  generally  (particularly  United 

States),  South  of  Europe,  Germany,  Africa,  Australia. 
Millet  or  Durra — East  Indies,  South  of  Europe,  Egj'pt,  Central 

Africa,  West  Indies. 
Manioc  or  Cassava — Tropical  America  (Brazil,  West  Indies,  etc. ) 

and  Africa. 
Nutmeg — East  Indies,  also  India,  West  Indies,  Brazil. 
Oats — Britain  (especially  Scotland),  Continental  Europe,  North 

America,  and  Australia. 
Olive — Syria  and  other  Asiatic  countries,  and  south  of  Europe. 
Opium — India,  Persia,  Asiatic  Turkey,  Egypt. 
Oranges — Azores,  Malta,  Sicily,  Spain  and  I'ortugal. 
Pine-apple — West  Indies,  and  many  other  tropical  and  sub-tropi- 
cal countries. 
Pine-timber — The  Baltic  countries,  and  British  North  America, 
Potato — America  (except  within  the  Tropics)  and  Europe. 
Prunes — France. 

Raisins — Spain  and  Asiatic  Turkey. 

Rhubarb  (Drug) — Inland  China,  Tibet,  and  Chinese  Tartary. 
Rice — India,  China,  South-east  of  Asia,  Japan,  Eg}'pt,  Southern 

States  of  North  America, 


133  PHYSICAL   GEOGRAPHY. 

Rosewood — Soutli  America,  and  Malabar  in  India. 

Rye — North  of  Europe,  and  some  parts  of  Asia. 

Sago — Borneo,  Singapore,  India,  Ceylon. 

Sugar  (Cane) — West  Indies,  Brazil,  Demerara,  Venezuela,    East 

Indies,  India,  Mauritius. 
Sugar  (Beetroot) — France,  Belgium,  Germany. 
Sugar  (Maple) — British  North  America  and  United  States. 
Tea — China,  Assam  (India). 
Teak — East  Indies,  India,  Further  India,  Africa. 
Tobacco — United  States,  Germany,  Turkey. 
"Walnut — South  of  Europe,  the  Himalayas,  and  North  America. 
Wheat — United  States  (Northern),    Germany,    Eussia,    France, 

British  North  America. 
Wines — Spain,    Portugal,    France,    Germany,    Hungary,    Capo 

Colony,  Australia. 
Yam — East  and  West  Indies. 


EXERCISES. 

Write  out  an  account  of  the  general  characteristics  and  dlstrt- 
Lution  of  plants.  Learn  from  the  map  the  distribution  or  chief 
localities  of  (1)  food-producing  plants;  (2)  clothing  plants;  (3) 
timber-trees;  (4)  medicinal  plants;  (5)  spices;  (6)  beverages,  etc. 
Which  of  these  are  gi-own  in  Britain?  Which  of  their  products 
are  imported?  Name  as  many  representative  species  and  as  many 
transferred  species  as  you  can,  besides  those  mentioned  in  the 
text.  Name  the  countries  em])raced  under  each  of  the  Zones  of 
Vegetation.  Draw  a  sketch  of  the  Ascending  Zones  of  Vegeta- 
tion; also,  map  of  Plant  Distribution. 


CHAPTER  VIII. 
DISTPJBUTION  OF  ANi:\rALS. 

General  Distribution — Distribution  according  to  Zones — Marine 
Animals — Animals  Peculiar  to  Certain  Regions — Representa- 
tive Species — Transferred  Species — Chief  Animal  Products 
and  the  Countries  of  their  Production. 

78.  General  Distribution. — There  are  250,000  kno^v^i 
species  of  animals.     Being  dependent  upon  climate  and 


GENERAL   DISTRIBUTION    OF   ANIMALS.  130 

food,  they  are,  like  pLants,  more  or  less  restricted  in  tlicir 
habitats;  and  they  have  also,  in  a  general  way,  both  a 
horizontal  and  a  vertical  distribution.  Within  the  Tropics 
animal  life  is  also  most  exuberant  in  point  of  size,  num- 
bers, strength,  and  beauty  :  the  Temperate  Zones  excel,  in 
these  respects,  the  Arctic  and  Antarctic,  with  the  excep- 
tion of  marine  animals  and  scafov/l,  which  are  most 
abundant  in  the  Polar  regions.  The  inhabitants  of  the 
rich  and  sheltered  lowlands  are  distinct  from  those  of  the 
mountain  slopes,  and  these  again  from  those  of  the  higher 
and  colder  elevations.  In  the  same  manner,  the  sea-fish 
of  the  shallow  shore  differ  from  those  of  the  deeper 
ocean.  •- 

The  Tropical  Eegions  are  the  abode  of  the  larger 
carnivora,  as  lions,  tigers,  etc.;  the  elephant,  rhinoceros, 
hippopotamus;  the  crocodile,  turtle,  boa,  and  larger  rep- 
tiles; the  ostrich,  flamingo,  peacock,  parrots,  humming- 
birds, and  others  of  varied  and  brilliant  plumage;  the 
giraffe  and  zebra,  apes  and  monkeys;  while  insect  life  is 
by  far  the  most  exuberant,  brilliant,  and  varied.  Mos- 
quitoes abound  in  America,  but  are  found  in  most  tropical 
countries;  locusts  infest  the  shores  of  the  Mediterranean 
and  the  East  generally;  ants  abound  chiefly  in  hot  and 
dry  countries — the  termites  in  Africa,  the  white  ants  in 
India.  In  the  swamps  of  the  great  rivers  of  tropical 
America,  the  air  is  one  dense  cloud  of  poisonous  insects 
to  the  height  of  twcntv  feet. 

The  Temperate  Zones  are  the  hcad-rpiarters  of  the 
ox,  bison,  butfalo,  goat,  sheep,  deer,'camel,  and  other  rumi- 
nants; the  wild  boar,  wolf,  fox,  and  beaver;  the  eagle, 
turkey,  goose,  grouse,  pheasant,  etc. 

The  Arctic  fauna  has  greater  uniformity,  ha-^nng  few 
species,  but  many  individuals,  with  a  less  varied  and 
more  sombre  colouring.  The  reindeer,  musk-ox,  brown 
and  polar  bears,  Arctic  fox,  and  numerous  fur-bearing 
animals,  are  peculiar  to  the  Arctic  Zone.  The  countless 
multitudes  of  sea-fowl  that  frequent  its  waters  are 
niigmnts  from  more  southern  latitudes,  and  reptile  life 


140  PHYSICAL   GEOGRAPHY. 

is  iinkno^Ti.  The  whale,  tlie  walrus,  and  the  seal  of  the 
polar  seas,  seem  the  counterparts  of  the  elephant,  the 
rhinoceros,  and  the  hippopotamus  of  tropical  climates. 

79.  Marine  Animals. — The  fishes  and  shell-fish  (and 
even  the  sea-weed)  of  the  Torrid  Zone  are  characterized  bj 
the  variety  of  their  genera  and  species,  and  they  are  of 
the  most  varied  and  brilliant  tints.  But  the  fish  of 
warm  waters  are  inferior  in  flavour  and  nutritious  quali- 
ties to  those  of  colder  seas.  The  true  pearl  oyster  is 
confined  to  the  Indian  seas.  The  shark  inhabits  the 
Torrid  Zone;  the  tunny,  the  Mediterranean;  while  the 
herring,  the  cod,  the  pilchard,  and  the  salmon,  reach 
perfection  only  in  colder  latitudes.  The  coral  insect 
builds  its  structure  only  in  tropical  or  sub-tropical  ex- 
panses. Tlie  sperm  whale  is  never  found  out  of  the 
tropical  areas  of  the  Pacific,  and  the  "right"  whale 
ncATr  out  of  colder  latitudes. 

80.  Animals  Peculiar  to  Certain  Regions. — Each 
quarter  of  the  world  has  some  one  class  of  animals 
predominant :  Europe  and  Asia  have  the  ruminantia; 
Africa  has  land  -  tortoises  ;  North  America,  birds  of 
i:)assage ;  South  America,  the  edentata,  or  toothless 
animals,  such  as  the  ant-eater,  armadillo,  and  sloth ; 
Australia,  the  marsupialia,  or  2'^ouched  animals,  such  as 
the  kangaroo.  Almost  every  country,  too,  has  animals 
peculiar  to  itself:  the  kangaroo  and  ornithorynchus  are 
confined  to  Australia,  the  red  grouse  to  Great  Britain, 
the  canary  to  the  Canary  Islands,  the  ichneumon  to  Egypt, 
the  hippopotamus  and  giraflfe  to  Africa,  true  humming- 
birds and  prehensile-tailed  monkeys  to  America;  the  camel 
to  the  dry  desert  regions  of  Africa  and  Asia,  and  the  rein- 
deer to  the  Arctic  Zone.  The  chamois  and  ibex  are  peculiar 
to  the  AljDS,  the  llama,  the  alpaca,  and  the  condor  to  the 
Andes  of  Peru,  the  yak  or  cashgow  to  the  table-land  of 
Tibet.  The  tsetse,  an  insect  of  South  Africa,  whose  bite 
is  death  to  certain  animals,  is  often  confined  to  the  region* 
lying  on  one  side  of  a  river.  In  the  South  Sea  Islands, 
just  as  in  Ireland,  there  are  no  serpents;  and  all  the 


ANIMALS    PECULIAR   TO    CERTAIN    REGIONS. 


U\ 


reptiles  of  the  New  World  are  distinct  from  those  of  the 
Old.  There  is  not  a  single  ruminant  animal  native  to 
Australia,  New  Guinea,  Madagascar,  and  the  South  Sea 
Islands;  and  of  the  whole  18G  species  of  ruminants,  only 
21  bcloniir  to  America. 

The  fauna  (or  animal-life)  as  well  as  the  flora  (or  plant- 
life)  of  Australia  is  the  most  peculiar  in  the  world; 
whilst  its  native  species  are  all  unknown  elsewhere, 
except  in  Tasmania.  Three  great  orders  of  animals  are 
entirely  awanting, — viz.,  the  ruminantia,  or  those  that 
chew  the  cud,  like  the  ox  or  sheep;  the  pachydermata,  or 
thick-skinned  animals,  like  the  horse  or  elephant;  and  the 
quadrumana,  or  four-handed  animals,  such  as  apes  and 
monkeys.  It  has  only  seven  species  of  carnivora,  viz., 
4  seals,  2  bats,  and  1  dog,  while  South  America  has 
only  13. 


ms   APTEUYX. 


The  complete  isolation  of  insular  f,TOups  is  still  more  remark- 
able. Out  of  2o  species  of  land  birds  in  the  CJaLipalos  islands, 
one  only  is  known  in  any  part  of  the  world.     Australia  baa  320 


142  PHYSICAL   GEOGRAPHY. 

species  of  birds,  and  of  these  290  are  found  nowhere  else.  A 
like  isolation  is  seen  in  New  Zealand,  1150  miles  distant,  whose 
most  remarkable  group  is  that  of  the  wingless  birds  {Aj^teryx). 

81.  Representative  Species. — Kegions  distant  from  each 
other,  having  similar  conditions  of  life,  just  as  with  plants, 
have  not  the  same,  but  often  representative  or  analogous 
species  of  animals.  Thus,  the  camel  of  the  Old  World  is 
represented  by  the  llama  and  alpaca  of  the  New;  the  lion 
and  tiger  of  the  Old  by  the  puma  and  jaguar  of  the  New; 
the  ostrich  of  Africa  by  the  rhea  of  South  America  and 
the  emu  of  Australia;  and  the  crocodile  of  the  Nile  by 
the  gavial  of  the  Ganges  and  the  alligator  or  cayman  of 
the  Amazon  and  Orinoco.  The  tapir  of  America  repre- 
sents the  elephant,  and  the  peccary  the  hog. 

82.  Transferred  Species. — Whilst  certain  animals,  such 
as  the  camel  and  the  reindeer,  cease  to  exist  away  from 
their  peculiar  habitat,  certain  other  species,  like  plants, 
have  been  transferred  by  man  from  their  native  regions 
to  others  for  the  purposes  of  convenience  or  luxury. 
Thus,  all  the  domestic  animals,  the  ox,  horse,  sheep,  dog, 
etc.,  many  birds,  and  even  vermin,  such  as  rats  and  mice, 
have  followed  man  over  the  habitable  globe.  "  The 
pampas  of  South  America  swarm  with  wild  cattle  and 
horses,  the  descendants  of  European  breeds."  Europe 
itself  owes  the  domestic  fowls  (except  the  turkey  from 
America),  and  probably  also  the  horse,  to  Asia.  But  the 
dog  is  the  only  animal  that  can  adapt  itself  to  all  cli- 
mates, and  thus  become  the  never-failing  companion  and 
devoted  friend  of  man.  Beyond  Eiu-ope,  however,  and 
the  countries  settled  by  Europeans,  the  dog  has  never 
been  domesticated. 

ANIMAL  PRODUCTS  AND  THE  CHIEF  COUNTRIES  OF 

THEIR  PRODUCTION. 

Cochineal  (Insect)— Mexico,  West  Indies,  Teneriffe,  Algeria. 

Fish— Herring,  haddock,  oyster,  cod,  or  ling,  in  the  British  seas- 
cod  also  in  Newfoundland ;  salmon,  in  British  rivers ;  tunny, 
Ruchovyj  and  sardines,  in  the  Mediterranean;  lobsters  and 


MANKIND.  143 

turbots,   from  Nonvay;  wlialo  and  seal,  in  the  Greenland 
seas ;  the  sperm  whale,  in  the  South  seas. 
Furs— Hudson's  Bay  Territory,  ^Vliaska,  Northern  Russia,  and 

Siberia. 
Hides— The  Pampas,  Russia,  North  Germany,  Australia,  Capo 

Colony,  East  Indies, 
Ivory — Africa,  India,  and  Siberia  (fossil  ivory). 
Oils — Whale  oils,  from  the  Greenland  and  South  seas;  seal  oil, 

from  Newfoundland,   Greenland,    and   Labrador;    cod-liver 

oil,  from  Britain,  Norway,  and  Newfoundland. 
Ostrich  Feathers — Africa  generally,  and  Arabia. 
Pearls— Ceylon,  Persian  Gulf,  Cororaandel  Coast,  Panama  (South 

America),  and  St.  Margarita  (West  Indies). 
Silk— China,  Ital,v,  Turkey,  Greece. 
Tallow— Russia,  North  and  South  America,  India. 
Wools— Australia,   South  Africa,   East  Indies,   South  America, 

Germany, 


EXERCISES. 

Write  out  lists  of  the  principal  animals  of  each  zone,  and  give 
the  distinguishing  characteristics  of  its  animal  life.  Name  ani- 
mals peculiar  to  certain  regions,  and  representative  and  trans- 
ferred species,  besides  those  in  the  text.  Draw  a  chart  of  the 
world,  and  lay  down  in  their  respective  habitats  all  the  animals 
mentioned  in  the  text. 


CHAPTER  IX. 

MANKIND. 

General  Distribution — Races  of  Men. 

83.  General  Distribution. — Man  is  the  only  animal 
capable  of  adapting  himself  to  all  climates,  and  hence  few 
regions  have  been  discovered  of  which  he  is  not  an  in- 
habitant. "  Under  the  scorching  rays  of  a  tropical  sun, 
upon  the  banks  of  the  Senegal,  the  human  body  support*? 


144  PHYSICAL   GEOGRAPHY. 

a  heat  which  causes  spirits  of  wine  to  boil ;  and  in  the 
polar  regions  of  North-Eastern  Asia,  it  resists  a  cold 
which  freezes  mercury."  Unlike  plants  and  the  inferior 
animals,  which  are  most  highly  developed  within  the 
Tropics,  and  degenerate  towards  the  Poles,  man's  noblest 
type  is  found  in  the  Temperate  Zones.  The  lowest  and 
most  miserable  tribes,  physically  and  intellectually,  are 
found  occupying  the  extremities  of  the  continents. 
Such  are  the  Esquimaux  in  Arctic  North  America,  the 
Samoiedes  of  Ai^ctic  Asia,  the  Fuegians  of  South  America, 
the  Hottentots  and  Bosjesmen  of  South  Africa,  and  the 
aborigines  of  Australia.  But  to  this  there  are  several 
important  exceptions — the  Patagonians,  the  tallest  race 
known ;  the  CafFres,  a  bold  and  warlike  people ;  and  the 
Maoris  of  New  Zealand,  a  brave,  handsome,  and  intelli- 
gent race. 

Food. — "Within  the  Tropics  man  lives  chiefly  upon 
vegetables  ;  in  the  Polar  regions,  exclusively  upon 
animal  food — chiefly  fish ;  and  in  the  Temperate  Zones, 
upon  a  mixed  animal  and  vegetable  diet.  But  the 
race  is  not  distributed  according  to  Zones  or  latitudinal 
limits.      -'-^  "  ■ 

84.  Races  of  Men. — Though  all  of  one  species,  man- 
kind have  been  divided  into  many  varieties,  difiering 
chiefly  in  complexion,  feature,  form  of  skull,  hair,  etc., 
but  also  in  civilization,  language,  and  religion.  The  fol- 
lowing are  the  chief  varieties  : — 

I. — Caucasian  Bace. — Characteristics. — Eaii-  com- 
plexion, flomng  hair,  ample  beard,  oval  head,  regular 
features. 

Distribution. — It  is  dispersed  over  the  south-west  of 
Asia,  the  north  and  north-east  of  Africa,  and  nearly 
all  Europe.  It  has  also,  within  the  last  three  cen- 
turies, extended  largely  from  Europe  over  North  and 
South  America,  South  Africa,  Australia,  and  New 
Zealand. 

Branches. — The  Hindoo,  Persian,  Arab,  Circassian, 
Sclavonic,  Teutonic,  and  Celtic. 


RACES   OF    MEN. 


145 


It  is  termed  Caucasian,  from  the  Caucasian  Mountains 
— the  surrounding  region  being  (erroneously)  supposed  to 
have  been  the  original  seat  of  the  race.  It  is  also  (and 
properly)  termed  Indo-European,  as  it  extends  over  India 
and  Europe,  from  the  Ganges  to  Iceland. 

II.  —  MoNGOLiAN  PtACE.  —  Characteristics.  —  Com- 
plexion tawny  or  olive-yellow,  haii"  coarse  and  straight, 
beard  scanty,  head  square-shaped,  face  broad  and  flat, 
cheek-bones  high,  and  small  black  eyes  obliquely  set. 

Distribution. — It  extends  over  all  Central  and  Eastern 
Asia,  and  the  whole  Arctic  sea-board  of  the  Old  World 
and  the  Kew. 


1.  Caucasian. 


2.  ^longolian. 


3.  Negro  (pure  tj-pe). 


4.  Malayan. 


5.  Otto  Indian  of  Xoi  th 
America. 


CniEF  VARIETIES  OF  MANKIND. 

Branches. — The    Chinese,    Burmese,    Siamese,    and 
noi-'hbouring  nations,  Japanese,  Tibetans,  Tartars,  Turks, 


23  E 


K 


146  PHYSICAL   GEOGRArHY. 

the  Samoiecles,  and  other  tribes  of  Siberia.     In  Europe 

the  Turks  proper,  the  Magyars  of  Hungary,  the  i'inns 

and   Lapps  of  Northern  Russia,  and  the  Esquimaux  of 

Arctic  America,  are  Mongolians. 

^■^  III. — Negro  or  Ethiopic  Race. — Characteristics. — 

Skin  black,  hair  short  and  woolly,  skull  narrow,  forehead 

slanting,'cheek-bones  high,  nose  broad  and  flat,  thick  lips, 

and  projecting  jaws.     It  is  the  lowest  type,  approaching 

nearest  the  gorilla  and  monkey. 

Distribution. — It  occupies  the  whole  of  Africa  south 

of  the  Great  Desert ;  but  the  Hottentots  and  CafFres  are 

not  true  negroes.     Its  most  typical  form  is  found  on  the 

low  unhealthy  plains  and  river-deltas  of  the  west  coast. 

The  Gallas,  Nubians,  and  Copts  of  the  Nile  Valley  are 

the  most  intelligent,  are  of  a  dark-brown  colour,   and 

approximate  physically  and  intellectually  to  the  white 

race,   with  which  they  may  form  a  link  of  connection. 

Negroes    exist   largely    in    America,    especially   in   the 

United  States,   West  Indies,   and  Brazil,   having  been 

originally  conveyed  thither  as  slaves. 

The  Hottentots  are  more  akin  to  tlie  Mongohans  ;  having 
broad  foreheads,  high  cheek-bones,  oblique  eyes,  and  a  dirty 
olive-coloured  complexion.  "The  orbits  of  the  eyes  are  wide 
and  distant  from  each  other,  and  the  face  is  remarkable  for 
ugliness.  The  Kaffir  (or  Caffre)  races  are  a  tall,  well-made,  and 
generally  handsome  people,  of  a  dark-brown  or  bronze  colour, 
and  hair  in  short  woolly  tufts." 

Minor  Varieties. — (1)  The  Malays,  a  form  of  the 
Mongolian  Race,  occupy  Malaysia,  Australasia,  and  Poly- 
nesia.- They  are  subdivided  into — (a)  Malays  proper,  in 
Madagascar,  Malaysia,  and  Polynesia  ;  (b)  Papuan  or 
Oceanic  Negroes,  of  Australia,  New  Guinea,  New 
Hebrides,  and  Feejee  Islands — the  former  of  a  brown 
colour,  the  latter  dark,  and  approaching  the  Negro  type ; 
and  (c)  the  Maoris  of  New  Zealand. 

(2)  American  or  Red  Indians,  the  aborigines  of 
North  and  South  America — copper-coloured,  with  hair 
lank  and  black,  aquiline  nose,  and  tall,  slender  figure. 
They  are  also  a  variety  of  the  Mongolian  Race. 


POPULATIOJT,  1-17 

Colour. — TLo  Caucasians  aro  -svlilte,  tlic  Mongolians 
yellow,  the  Negroes  black,  the  Malays  brown,  and  tho 
Americans  red.  The  colour  is  due  to  the  presence  of  a 
pigment  which  fills  the  cells  that  lie  between  the  epidermis, 
or  outer  skin,  and  the  cutis,  or  second  skin,  and  which,  in 
the  case  of  tlie  white  man,  are  entii-ely  empty.  Summer 
freckles  are  due  to  the  same  cause.  But  the  colour  is 
greatly  modified  in  the  case  of  tribes  occupying  high  and 
diy  plateaux  or  highland  regions,  and  is  comparatively 
Avhite. 

Numbers. — The  Caucasians  number  about  500,000,000, 
the  Mongolians  490,000,000,  the  Negi'oes  (including 
Papuans),  100,000,000,  the  Malays  60,000,000,  and  the 
American  Indians  16,000,000. 

85,  Civilization. — The  Caucasian  race  is  the  most 
civilized — the  most  eminent  nations  of  ancient  and  modern 
times  having  sprung  from  it.  The  Mongolians  are  inferior 
to  them  intellectually  and  morally;  their  civilization,  most 
advanced  among  the  Chinese  and  Japanese,  is  of  a 
stationaiy  character.  The  Americans  have  also  remained 
stationary,  and  are  now  fast  disappearing  before  tho 
white  man.  The  Negro  is  the  lowest  of  the  three  gi'eat 
races.  He  has  always  remained  in  a  state  of  barbarism 
and  slavery  to  the  whites.  The  Malays  proper  are^  a 
hardy  and  enterprising  mce ;  but  the  natives  of  Australia, 
miserable  and  stunted,  occupy  the  lowest  place  in  tho 
scale  of  humanity. 


Population  of  the  Globe. 

-"»■  Average  per  sq.  mile, 

Europe, 282,000,000 73  persons. 

Asia, 711,000,000 40 

Africa, 130,000,000 11 

Korth  America, 50,000,000 G 

South  America, 22,000,000 3-5     „ 

Oceania, 20,000,000 45     „ 


1,215,000,000 


U8  PHYSICAL   GEOGRAPHY. 


Density  of  Population. 


Per  sq.  m. 

Bermuda, 477 

Belgium, 433 

China  proper,  288 

Netherlands,  275 

Great  Britain  &  Ireland,. 245 
Japan, 233 


Per  sq.  m. 
Massachusetts  (U.  S.),...157 
United  States,  generally,   11-3 
Iceland  and  Faroe  Isles, .     1 S 
Basin  of  Amazon,  1  per  10  sq.  m. 

Patagonia, 8  per  100  sq.  m. 

Greenland, 1  „ 


SujvniARY  OF  Religions. 

Roman  Catholics, 185,000,000) 

Protestants, 95, 000, 000  }  Christians,  355, 000, 000 

Greek  Church, 75,000,000) 

Jews, 7,000,000 

Mohammedans, 120,000,000 

Hindoos, 120,000,000  ) 

Buddhists, 400, 000, 000  }  Heathens, . .  733, 000, 000 

Other  Idolators, 213,000,000  )  

1,215,000,000 


EXERCISES. 

1.  Give  reasons  to  account  for  man's  capability  of  adaptation  to 
all  climates.  Write  out  in  tabular  form  the  races  of  men,  with 
their  characteristics,  distribution,  chief  sub- divisions,  and  state 
of  civilization.  To  which  race,  and  which  of  its  branches,  do  the 
people  of  Great  Britain  and  Ireland  belong  ?  Lay  down  on  a  map 
of  the  world  the  Distribution  of  the  Races  of  Men. 


SPECIMEN  EXAMINATION  PAPERS. 


General  Ixstructions. 


You  are  only  permitted  to  answer  questions  from  the  elemen- 
tary paper  or  from  the  advanced  paper,  but  not  from  both.  If 
the  rules  are  not  attended  to,  the  paper  will  be  cancelled. 

In  all  cases  the  number  of  the  question  must  be  placed  before 
the  answer  on  the  worked  paper. 

Three  hours  are  allowed  for  this  paper. 


FIRST  STAGE  OR  ELEMENTARY  EXAMINATION 

Instructions. 

You  are  only  permitted  to  attempt  eight  questions. 

You  must  attempt  the  first  three  questions  on  the  paper.  The 
remaining  five  you  may  select  from  any  part  of  the  paper. 

The  value  attached  to  each  of  the  first  three  questions  is  10 
marks.  The  value  of  each  of  the  remaining  questions  is  14 
marks.  But  a  full  and  correct  answer  to  an  easy  question  will 
in  all  cases  secure  a  larger  number  of  marks,  than  au  incomplete 
or  inex*ict  answer  to  a  more  diflScult  one. 


1  "NMiat  is  the  figure  of  the  earth  ?  WTiat  is  the  equator  ? 
And  what  are  the  poles  ? 

2.  What  is  the  proportion  of  the  earth's  surface  that  is  covered 
by  water  ?     Is  there  more  water  north  or  south  of  tlie  equator  ? 

3.  What  are  the  two  principal  rivers  of  India?  From  wliat 
mountain  chain  do  they  originate  ?  Into  what  seas  do  they 
enter  ?     And  with  wliat  ocean  do  tliese  seas  communicate  ? 

4.  What  is  the  position  of  tlie  Alpine  mountain  system  in 
Europe  ?  What  are  the  principal  spurs  or  branches  proceeding 
from  it  ?    What  Ls  the  direction  of  each  ? 


150  QUESTIONS. 

5.  "What  is  the  general  form  of  the  bed  of  tiie  Atlantic  Ibetweeil 
Ireland  and  Newfoundland  ?  AVliat  is  the  greatest  depth  of 
water  in  this  part  of  the  ocean  ? 

6.  Mention  the  prevalent  winds  experienced  by  a  shiiD  proceed- 
ing from  London  to  the  West  Indies. 

7.  What  is  a  cloud  ?  What  are  the  varieties  of  clouds  ? 
What  is  the  relative  height  of  the  different  groups  of  clouds  ? 

8.  Compare  the  climates  of  Ireland  and  Newfoundland.  What 
are  the  causes  of  the  difference  of  climate  in  these  two  localities  ? 

9.  What  is  a  volcano  ?  What  are  the  substances  ejected 
during  an  ordinary  volcanic  eruption  ? 

10.  Mention  some  of  the  principal  food  plants,  the  places 
whence  they  were  originally  obtained,  and  the  parts  of  the  earth 
where  they  are  chiefly  consumed. 

11.  What  is  the  limit  of  distribution  of  monkeys  ?  What  are 
the  difierences  between  the  four-handed  anim.als  of  the  Old 
World  and  America  ? 

12.  Compare  the  native  races  of  men  of  tropical  Africa  with 
those  of  tropical  America. 

II. 

1.  Explain  what  is  meant  by  longitude.  What  is  the  length 
of  a  degree  of  longitude  at  the  equator  and  in  the  latitude  of 
London  ? 

2.  What  are  the  chief  promontories  of  Asia  ?  In  what  direc- 
tion do  they  point  ?  What  is  the  form  of  Africa  ?  (a  diagram  if 
preferred). 

3.  Name  (a)  a  large  inland  sea  communicating  with  the  ocean, 
(h)  a  salt  lake,  (c)  an  important  fresh-water  lake.  State  in  each 
case  the  geographical  position. 

4.  What  is  the  origin  of  rain  ?  Why  is  rain  distributed  un- 
equally over  the  earth  ?  Mention  certain  districts  without  rain 
in  ordinary  years.  : 

5.  "What  is  dew  ?  Mention  the  conditions  of  the  air  favour- 
able and  unfavourable  for  its  deposit.  What  is  the  season  of 
heaviest  dew  in  the  British  Islands  ? 

6.  Name  one  of  the  great  rivers  in  the  Old  World.  State  the 
position  of  its  chief  sources,  and  their  height  above  the  sea,  the 
names  of  the  chief  tributaries,  the  circumstances  under  which 
the  river  reaches  the  sea,  and  the  countries  it  passes  through. 

7.  Explain  the  difference  between  the  tidal  wave  in  the  open 
Atlantic  and  the  tidal  wave  advancing  up  the  Enghsh  Channel.  . 

8.  What  is  the  air  ?  What  are  wind  storms ;  and  what  is  the 
difference  between  periodical  and  permanent  winds  ? 

9.  Where  is  Mount  Hecla  ?  Give  proof  of  the  existence  of 
Bubterraneaft  communication  between  Etna  and  Vesuvius.    Men- 


QUESTIONS.  151 

tioh  tliiotiiet-  European  active   volcano   (not  in  Italy)   and  its 
l)osition. 

10.  Mention  two  food-plants  and  two  tribes  of  animals  all 
characteristic  of  the  tropics.  Mention  corresponding  plants  and 
animals  in  temperate  climates, 

11.  Point  out  an  essential  difference  between  the  monkej's  of 
the  Old  and  New  Worlds.  To  which  of  the  six  principal  divi- 
sions of  the  land  are  monkeys  now  limited  ?  "What  are  the 
characteristic  carnivora  of  Asia,  and  what  the  genera  that  most 
nearly  represent  them  in  South  America  and  Australia  ? 

12.  "What  is  the  geographical  home  of  the  negro  ?  "^^^lat  are 
the  two  principal  varieties  of  the  negro  in  South  Africa?  De- 
scribe some  of  the  marked  peculiarities  of  the  true  negro  and 
these  two  varieties. 


III. 

1.  "What  is  meant  by  Phj-sical  Geogi\nphy?  How  does  Physical 
Geography  differ  from  Descriptive  Geography  and  from  Geology? 

2.  Explain  the  meaning  oi  the  following  terms,  and  give  an 
example  of  each:  (a)  Mountain  system,  (h)  River  system. 

.3.  AVhat  is  a  volcano  ?  A\'here  are  the  principal  groiips  of 
volcanoes  ?     Name  the  chief  volcanoes  of  Europe. 

4.  What  are  the  three  great  oceans  ?  Do  the  great  oceans 
open  into  each  other,  and,  if  so,  by  what  channels  ?  "What  are 
the  largest  islands,  and  where  are  they  situated  ? 

5.  Explain  in  what  way  a  broken  and  irregular  coast-line  may 
be  an  advantage  to  a  countrv.  ^Mention  an  island  remarkable 
for  its  irregularity  of  coast.  Mention  some  large  tract  of  land 
ha\'ing  an  unbroken  coast-line. 

<3.  Give  an  account  of  the  whole  course  of  some  important 
river,  mentioning  its  sources,  its  chief  tributaries,  its  lakes  and 
waterfalls,  and  the  circumstances  under  which  it  reaches  the  sea. 

7.  What  is  a  glacier  ?   Where  are  the  chief  glaciers  of  Europe? 

8.  Describe  the  trade-winds,  and  explain  their  cause. 

9.  In  what  countries  near  the  sea-level,  and  within  what  alti- 
tudes within  the  tropics,  do  pines  grow  freely  ?  What  food 
plants  are  most  common  in  the  pine  region  ? 

10.  In  what  countries  are  humming-birds  found  ?  Within 
what  limits  are  birds  of  brilliant  plumage  for  the  most  part  con- 
fined ?     To  what  countries  is  the  ostrich  limited  ? 

11.  What  proof  is  there  that  the  human  race  existed  on  the 
earth  at  a  time  when  the  climate  was  very  different  from  that 
which  now  prevails  ? 

'  12.  ^Mention  some  of  the  more  striking  changes  produced  in 
Australia  on  the  distribution  of  qua/lrupeds  since  the  countr/ 
has  become  partially  occupied  by  civilized  racei^ 


INDEX. 


Africa  and  S.  America  Compared,  20. 
Agricultural  Zones,  135. 
Amazon,  72. 
American  Desert,  42. 

,,  Earthquake  District,  126. 

,,  Indians,  146. 

Andes,  2S. 
Animals,  Distribution  of,  138,  139. 

„         Marine,  1-10. 

„        of  Arctic  Zone,  139. 

„        of  Temperate  Zone,  139. 

„         of  Tropics,  139. 

„        of  the  Continents,  140. 

„        Peculiar  to  Certain  Regions, 
140. 

„        Products,  142. 

,,        Representative  Species,  142. 

,,        Transferred  „  142. 

Annual  Floods,  75. 
Antarctic  Drift  Current,  63. 
Antipodes,  9. 

,,        Islands,  17. 
Apteryx,  141. 
Aqiieous  Rocks,  113. 
Aral  Lake,  25,  SO. 
Archipelagoes,  13 

,,  Largest,  22. 

Arctic  Current,  64. 
Atlantic,  Bottom  of,  53. 
Atmosphere,  S5,  110. 
Atolls,  129. 
Australasia,  16. 
Australia,  16,  18,  21,  42, 134. 
Avalanches,  107. 

Bank,  15. 

Barrier  Reefs,  139. 

Basins  of  Continental  Streams,  70. 

Bavaria,  Plateau  of,  38. 

Binai-y  River  System,  70. 

Bohemia,  Plateau  of,  38. 

Bolivia,  „  33. 

Bora,  92. 

Bore,  61. 

Botanic  Regions,  133,  134. 

Brazil  Current,  -63. 

Calms,  98. 

Cascade  or  Cataract,  72. 
Caspian  Sea,  25,  80. 


Caucasian  Race,  144. 
Central  Asia,  34,  126. 

,,         Heat  of  the  Earth,  119. 
,,        Plain  of  America,  42. 
,,        Volcanic  System,  123. 
Cereals,  135. 
China,  Plain  of,  41. 
Cirrus,  or  Curl  Cloud,  100. 
Civilisation  of  Mankind,  147. 
Climate,  93. 

,,        Continental  and  Jraritime,95. 
,,         Influence  on  Health,  110. 
,,        Influenced  by  Gulf  Stream, 

64. 
„        Influenced  by  Altitude,  94. 
,,  ,,  Latitude,  94. 

,,         Summary  of  Causes  of.  111. 
Clouds,  99-102. 
Coal,  114,  116,  118. 
Coast  Lines,  20. 
Coffee,  136. 
Cold  Winds,  92,  93. 
Coldest  Region  of  the  Globe,  97. 
Colour  of  Water  of  Sea,  57. 

,,       of  Mankind,  143. 
Constant  Currents,  61. 
,,        Rains,  105. 

,,  ,,     Countries  of,  105,  106. 

,,        Winds,  87. 
Constantly  Frozen  Ground,  97. 
Continents,  Eastern  and  Western,  16. 
,,        North  and  South  Points,  20. 
,,        Points  of  Resemblance,  19. 
,,        Size  of,  18. 
Continental  Islands,  22. 

,,        Rivers,  70. 
Copper,  118. 

Coral  Formations,  128-130. 
„      Insects,  128. 
,,      Islands,  50. 
Cotton,  136,  137. 

Counter  Current  of  Indian  Ocean,  63. 
Crater,  119. 
Creek,  15,  75. 
Crevasses,  108. 
Crust  of  the  Earth,  112. 
Cumulus  or  Summer  Cloud,  100 
Currents,  61-65. 

„        Causes  of,  62. 

„        Directions  of,  62,  65 


INDEX. 


153 


Currents,  Equatorial,  62,  63. 

,,        Uses  of,  65. 
Cyclouee,  91. 

Daily  Floods  of  Rivers,  75. 

Panvibe,  Middle  and  Lower,  41. 

Dead  Sea,  25,  70,  SO,  81. 

Deccan,  35. 

Deep-Sea  Currents,  62. 

Deep-Seated  Springs,  67. 

Delta,  15,  23,  75. 

Density  of  Population,  143. 

Depth  of  the  Oceans,  53. 

Deserts,  44. 

Desert  of  Atacama,  106, 

Dew  and  Dew  Point,  98. 

Doldrums,  93. 

Drift  Currents,  61. 

Dry  Season,  104. 

Dunes,  41. 

Earth,  Central  Heat  of,  110. 

„        Form,  Size,  and  Motions,  9, 10. 

„        Mathematical  Divisions,  11. 

,,        Natural  Divisions,  13. 

,,        Orbit  of,  10. 

„     •  Rotundity  of,  9. 
Eartliquakes,  125-128. 
Earthquake  Districts,  126. 
„         Effects  of,  126. 
,,  of  Lisbon,  126. 

,,         of  South  America,  126. 
Easterly  "Windi,  90. 
Ecliptic,  12. 
El  Gran  Chaco,  44. 
Encircling  Reefs,  129. 
Equator,  11. 
Eruptive  Rocks,  113. 
Estuary,  15. 
Etesian  Winds,  02. 
Evaporation,  97. 

Fall  of  Rivers,  72. 

Fata  Morgana,  86. 

Fens,  41. 

Fiords,  74. 

Fire  Springs  and  Fire-Hills,  124, 

Fires  of  Baku,  124. 

Firth,  15,  76. 

Fish,  140,  142. 

Five  Great  Lakes,  81. 

Floods  of  Rivers,  75. 

Fogs,  98. 

Fohn,  92. 

Form  of  the  Earth,  9. 

Forms  of  Vertical  Arrangement  of 

Land,  23. 
Fossiliferous  Rocks,  114,  115. 
Freezing-ix)int  of  Water,  57. 
Fringe-Reefs,  130. 
Fumerolea,  124, 
FuiB,  143. 


Gallego,  92. 

Geography,  Physical,  Definition  of,  9. 

Germanic  Plain,  40. 

Geysers,  69,  124. 

Gobi,  35,  106. 

Gold,  116,  117. 

Glaciers,  103. 

Great  Northern  Plain,  SO. 

Great  Plain  of  Europe,  40. 

Guiana  Current,  63. 

Gulf  Stream,  63. 

Hatl,  110. 

Halos,  86. 

Ilan-IIai,  35. 

Harbour  or  Haven,  15. 

Harmattan,  91. 

Heat,  Distribution  of,  96. 

Hemp,  136,  137. 

Hides,  143. 

High-water,  60. 

Hills,  29. 

Himalayas,  29, 

Hindostan,  Plains  of,  41. 

Hoar-Frost,  98. 

Horizontal  Eavtliqnakes,  125. 

,,         Configuration  of  Land, 
19-22. 
Horse-Latitudes,  93. 
Hot  Winds,  91,  92. 
Hottest  Region  of  the  Globe,  97. 
Hurricanes,  90. 

Icebergs  and  Ice-Floes,  109. 

Iceland  Earthquake  District,  128. 

Ice-packs,  109. 

Igneous  Rocks,  113. 

Inland  Seas  of  the  Atlantic,  51. 

Insular  Climate,  95. 

Iran,  Plateau  of,  35. 

Iron,  116,  118. 

Island  System,  21. 

Island,  Largest,  22. 

Isotherms,  96. 

Japan  Current,  63. 

Karroos,  35. 
Khamsin,  91. 

Lagoon,  15. 
Lagoon  Islands,  129. 
Lakes,  80. 

,,    Classification  of,  SO,  SL 

,,     Distribution,  81. 

,,     Piincipal,  82. 

,,     Uses  of,  81,  82. 
Land-Breezes.  89. 
Land,  Forms  of,  24. 
„      Horizontal  Configaratioa, 
19-22. 


154 


INDEX. 


Land,  Vertical  Configuration,  23-1(5. 

„       Laws  of  Configuration,  25-27. 

,,      Points  of  Resemblance,  19. 

„      and  Water,  Distribution  of, 
10,  17. 

,,      and  Water,  General  Aspect,  IC, 

„      and  Water  Hemispheres,  17. 
and  Water,  Mutual  Relations, 
52. 

„      and  Water,  Relative  Propor- 
tions, 16. 
Landes,  41. 
Land  Springs,  67. 
Latitude,  12. 
Las  Salinas,  44. 
Lead,  117. 

Life  in  the  Ocean  Depths,  54. 
Linear  Volcanic  System,  123. 
Llanos,  43, 
Local  Winds,  91-93. 
London,  Centre  of  Land  Hemisi^here, 

17. 
Longitude,  12. 
Low -Water,  60. 

Maize,  135, 137. 
Blalay  Race,  146. 
Mankind,  143-143. 

Civilization  of,  147. 
„         Distribution  of,  143-140. 
„  Races  of,  144-146. 

Marine  Animals,  140. 
Maritime  Climate,  95. 
Jlediterranean  Earthquake  Basin,  126. 
I^Iean  Elevation  of  Continents,  46,  47. 
Mercury,  117. 

Jlesopotamia,  Plains  of,  41. 
Meridians,  12. 

3Ietamorphic  Rocks,  1L3,  115. 
Mexico,  Plateau  of,  37. 
Minerals,  Distribution  of,  117. 
Mineral  Springs,  OS. 
Mirage,  815. 
Mist,  98, 
Jlistral,  92. 
Mock-Suns,  86. 
Moisture,  97-110. 
Mongolian  Race,  145. 
Jlonsoons,  SO. 
Moraines,  108. 
Jlotions  of  the  Earth,  10. 
Mountains,  27-33. 

„  Axis  of  the  Globe,  26. 

„  Configuration  of,  27. 

Chains,  28. 

Chief  Ranges,  31-33. 

Dimensions  of,  29, 

Height  of,  28,  29. 

Highest  Summits,  31-33. 

Isolated,  28. 

Principal,  31-33. 


»» 


»> 


Mountains,  Secondary  Rafiges,  2G. 

Slope  and  Counter-slope, 
28. 

Systems,  14,  31-33. 

Uses  of,  30. 

and  Rains,  103,  104. 
jrove'ments  of  the  Ocean,  58-65. 
Mud  Vokanoes,  124. 
Mutual  Relation  of  Land  and  Water, 
52.  ,. 

Neap-tides,  50. 

Negro  Race,  146. 

New  South  Wales  CuiTent,  63. 

New  Zealand  Current,  63. 

Niagara  Falls,  72,  73. 

Nile  Valley,  36. 

Nimbus  or  Rain  Cloud,  101. 

North-west  Passage,  51. 

North-west  Winds,  89. 

Nullah,  75. 

Oasis,  36. 

Ocean,  Antarctic,  51,  52. 
„      Arctic,  51.  52. 
Atlantic,  49,  51. 

Inland  Seas  of,  51. 
Depth  of,  53. 
Vertical    Section  of, 
55. 

,,      Colour  of,  57. 
Oceans,  compared  with  Continents, 49. 
Configuration  of,  50-52. 
Depth  of,  53,  54. 
Dimensions  of,  50. 
,,      Divisions  of,  49. 
„      Indian,  49. 
,,      Life  at  Bottom  of,  56. 
,,       Pacific,  49. 

„  „    Land-locked  Seas  of,  50. 

,,       Saltness  of,  56. 
,,      Temperature,  56. 
Oceania,  16-18. 
Oceanic  Rivers,  69. 
Oils,  143. 

Pamir,  35. 
Pampas,  43. 
Pampero,  92. 
Parallels  of  Latitude,  12. 
Pearls,  143. 
Peninsulas,  19. 

,,  of  Europe  and  Asia,  19. 

Periodical  Currents,  61. 
„  Rains,  104. 

Winds,  89. 
Petroleum,  118. 

Physical  Geography,  Definition  of,  9. 
Pine-barrens,  43. 
Plains,  39-44. 

„      of  America,  44. 


ft 

>J  >» 

>»  >> 


INDEX. 


155 


plains  of  Africa,  44. 
,,      of  Asia,  43. 
,,      of  Europe,  4^. 
,,      Secondary,  41. 
,,      Uses  of,  44. 
Plants,  Characteristics  of,  131. 

,,       Distribution  of,  162. 
Plateaux,  34-3S. 

„         Dryness  of,  103. 
,,  of  Africa,  35,  3G, 

„         of  Asia,  34. 
,,  of  Europe,  34. 

,,         Valleys  of,  40. 
riatinnni,  117. 
Po,  Valley  of,  41. 
Polar  Circles,  12. 
,,      Vegetation,  132. 
„      -Winds,  SS. 
Polders,  23,  40,  41. 
Potato,  135,  137. 
Polynesia,  50. 
Population  of  the  Globe,  147. 

,,  Density  of,  147. 

Precious  Stones,  117. 
Pressure  of  Water,  54. 
Puna  Winds,  92. 

Rainbow,  86. 
Pains,  102-lOG. 

,,       Classification  of,  104, 

,,       Distribution  of,  102. 
Rainfall  on  Coast  and  Inland,  lC-3. 
Painless  Regions,  105. 
Rainy  Sea,  105. 
Rainy  Season,  104. 
Rapids,  72. 
Red  Indians,  146. 
Religions,  Summary  of,  143. 
Representative    Si>ecie8  of   Animals, 
141. 

„  „  Plants,  134. 

Bice,  135,  137. 
Rivers,  69-79. 

,      Basin.?,  15,  71. 

,      CI  ass  ifi  cation  of,  CD. 

,,       Floods  of,  75. 

,,      Mouths  of,  74. 

„       Principal,  76-79. 

„      Sources  of,  70. 

,,       t^ystems  of,  15,  70. 

,,      United  at  Source,  71. 

„       Uses  of,  G9. 

,,       Valleys,  45,  46. 
Roads,  Roadstead,  15. 
Rocks,  113-115. 
R(jck-salt,  lis. 
Rotatory  Earthquakes,  125 

SAHAnA,  35,  36. 

Sainiel,  91. 

Baltuess  ejC  the  Sea,  59. 


Sargasso,  51. 

Sariuatian  Plain,  iO, 

Savannah, 14,  42. 

Sea  Breezes,  S9. 

Sedimentary  Uocks,  113, 

Selvas,  43. 

Shamo,  35,  106. 

Siberian  Plain,  40, 

Silk,  137,  13S. 

Silver,  117. 

Simoom,  91. 

Sir-i-Kol,  Lake,  81. 

Sirocco,  91. 

Size  of  the  Continents,  13. 

„  Earth,  143. 

,,  Oceans,  50. 

Slope  and    Counter-slope    of   Moun- 
tains, 28. 
Slopes  of  Old  and  New  World,  25,  26. 
Snow,  106-110. 
Snow-blanket,  107. 
Snow-limit,  9(5,  106. 
Snow-line,  94.  ''■ 

„         Height  of,  95, 
Solano,  91. 
Solfatara,  124. 

South  African  Currents,  63. 
South  America  and  Africa  compared, 

20. 
South-west  Winds,  89. 
Spain,  34. 
Springs,  67-69. 
Spring-tides,  59. 
Steppes,  40. 
Storms,  90.     ' 
Stratus,  or  Fall-Cloud,  101. 
Stratified  Rocks,  116. 
Sugar,  137,  138. 
Switzerland,  42. 

Tadle  Lands,  34-33. 

„  Valleva  of,  46. 

Tallow,  143. 
Tchad,  Lake,  70,  81. 
Tea,  136,  138. 
Temperature  of  the  Atmo."!pliere,  93. 

„  ,,        OcGau,  56. 

Temperate  Regions,  Vegetation,  132. 
Telegraphic  Plateau,  52. 
Thermal  Springs,  08. 
Tide- Waves,  60. 

,,  Velocity  of,  61. 

Tides,  58. 

,,      in  South  Seaa,  61. 
Tin,  118. 
Tobacco,  135,  133. 
Tornadoes,  90. 
Trade  Winds,  87,  103. 
Transtratic  Springs,  67. 
Tremulous  Eartlniuakes,  125. 
I  Tropics,  12. 


156 


INDEX. 


Tropical  Vegetation,  132. 
Tundras,  41. 
Twilight,  S6. 
Tjpboons,  or  Tyfoons,  90. 

Unstratified  Eocks,  115. 
Utah,  70,  83. 

Vallets,  45,  46. 
Variable  Currents,  61. 
„      Rains,  105. 
„       "Winds,  89. 
Vegetable  Products,  136-13S. 
Vegetation,  Ascending  Zones  of,  133. 
„  Tropical,  Temperate,  and 

Polar,  132. 
„  Zones  of,  133. 

Velocity  of  Rivers,  72. 

,,         Tide-waves,  60. 
Vent  de  Bise,  92. 
Vertical  Configuration  of  Land,  23-46. 

,,      Earthquakes,  125. 
Victoria  Falls,  73. 
„        Land,  26,  52. 
N'Yanza,  81. 
Volcanic  Agency,  Uses  of,  127,  123. 

„       Phenomena,  119. 
Volcanoes,  119-125. 

„         Classification  of,  123. 
„         Distribution  of,  121,  123. 


Volcanoes,  Effects  of,  124. 

Wadies,  75. 
Warmth,  Equator,  97. 
Waterfalls,  72-74. 
Waters  of  the  Land,  67-83. 
„  Ocean,  49-65. 

,,  ,,         .   Quantity  of,  54. 

Watershed,  15,  70. 
Waves,  53. 
Wheat,  135,  133. 
Whirlwinds,  91. 
Winds,  87-93. 

Classification  of,  87. 
Easterly  and  Westerly,  90. 

„      Formation  of,  87. 

,,       Local,  91-93. 
Wines,  136,  133. 
Wools,  143. 
World,  Old  and  New,  16. 

,,      Culminating  Points  of,  27. 

,,      Mountain  Axis  of,  26. 

„       Plains  of,  39,  42. 

,,       Rivers  of,  69. 

Zones,  Animals  of,  139. 
Areas  of,  13. 
Characteristics  of,  12, 
Heat  of,  96. 
Plant*  of,  132,  133. 


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